User:Wladek92/sandbox

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TemplateData is an extension that stores information and parameters associated with a wikitext template and makes it available to an editing interface that can retrieve and present it in a template editor -- all of which helps users add and edit templates on pages.

As of April 2019, template data functionality is part of the default user experience for all users on all Wikimedia wikis when they add a template, even unregistered users. Both the default source and visual editors incorporate it in some way, as do many scripts, tools and gadgets. If you want this functionality on your own wiki, install Extension:TemplateData .

Adding template data to a template for this extension to use involves inserting a small, simple block of JSON (explained below) into the template's documentation page. You can do this manually or with the template data editor, a graphical user interface you can access on a template's "Edit"/"Edit source" pages on wikis with the TemplateData extension installed. The JSON contains a list of the template's parameters and information about those parameters and about the template as a whole (see below for details).

Templates that contain template data will display this information in the user interface when a user adds the template. In some cases, it will change how the editor behaves when you use it to edit or insert a given template, making it much easier for users to perform the steps needed to add a given template.

History

Template data was originally developed in early 2013 with VisualEditor in mind, which was in MediaWiki testing stages at the time. The visual editor is the main visual editing interface for Wikimedia wikis, and template data allows it to have a more useful interface when adding templates. It was officially supported by the visual editor immediately. As the visual editor was rolled out to the various major Wikimedia wikis as a default feature from 2013 through 2016, template data became a part of them as well.

In December 2016, the visual editor interface was made available for editing source code as a beta feature. This was termed the 2017 wikitext editor . This brought the features of template data to source editing for the first time.

In March 2018, Sam Wilson developed TemplateWizard , a GUI template editor extension for the default Wikimedia source editor, WikiEditor (otherwise known as the 2010 wikitext editor), designed to make the process of adding templates easier by using information from template data. In April 2019, TemplateWizard was made a default part of the 2010 wikitext editor on all Wikimedia wikis. This meant that template data was now a default part of both the visual editor and the source editor on Wikimedia wikis.

Adding or editing template data

To add or edit template data, first navigate to a template's page, located at "/Template:Templatename".

Checking the current state

Before adding or editing template data, check whether the template has a documentation subpage. Then check whether the template already contains template data and, if so, whether it's located on the template page or the documentation subpage.

Be sure to check whether a subpage exists. If you add template data to a template's main page while a subpage exists with template data, the template data in the main page will override the data on the subpage.

Documentation subpages

There are two main ways templates on most Wikimedia wikis store their usage notes and other data that shouldn't be included in the actual template itself, like categories the template should be contained in:

• The vast majority of templates keep usage notes and other data that doesn't belong on the template page itself on a documentation subpage: "/Template:Templatename/doc". On pages like this, the {{Documentation }} template transcludes all the /doc page's content onto the template page, keeping the template's source code much cleaner.
  • On templates with documentation subpages, the " Template documentation" heading will be followed by links such as [view], [edit], [history] and [purge].

• A few template pages have retained that information on the template's main page. You can spot it on these pages by looking for an occurrence of {{Documentation|content= between ‎<noinclude> tags.

Different wikis may present all this differently. Rarely, main template pages may still contain documentation even when you've checked all of the foregoing; here, a user will have added a custom /doc page title between "{{Documentation|" and "|content=" and then added content after "|content=".

You can also look for a notice at the bottom of the page similar to this: "The above documentation is transcluded from Template:Templatename/doc".

Templates without documentation subpages

If a template doesn't have a documentation subpage, create it and move the template's documentation there (or a placeholder for it). Then you can add template data to the documentation subpage.

Creating the subpage and moving the documentation

On many Wikimedia wikis, you can only create a page if you have been a registered user there for a number of days and have made a minimum number of edits.

To create the documentation subpage, click "Edit"/"Edit source" on the main template page; look for the ‎<noinclude> tags and their contents (usually at the bottom).

It should look something like this:

<noinclude>
{{Documentation|content=
== Usage ==

Information about usage.

== More example headings ==

More example contents

[[Category:Example category]]
[[Category:Example category 2]]
}}
</noinclude>

You may also find that it already contains template data. If so, it will look something like this:

<noinclude>
{{Documentation|content=
...
<templatedata>
{
    "description": "",
    "params": {
        "1": {
            "label": "Example parameter",
            "description": "Example parameter description",
            "type": "string"
        }
    }
}
</templatedata>
</noinclude>

Select everything after "|content=" and before "‎</noinclude>" and cut it into your clipboard or save it in a temporary document. Delete "|content=", leaving only the following:

<noinclude>
{{Documentation}}
</noinclude>

Save the template page.

Now, to create the new subpage, look at your browser's address bar and add /doc to the end of the URL. Press ↵ Enter, then choose the option to create a new page.

If this wiki has a {{Documentation subpage }} notice template, add it at the top of the new page. You may also wish to add other templates, such as a {{Purge button }} or {{Purge }} link (if supported by the wiki in question).

Insert the text you cut or saved in the previous text (beneath the notice template, if applicable).

Wrap any categories in ‎<includeonly> tags so that they apply only to the template's main page:

<includeonly>
[[Category:Example category]]
[[Category:Example category 2]]
</includeonly>

Many wikis have a {{Sandbox other}} template. Use this template here if it's likely that the template you're editing exists in a sandbox version (located at "Template:Templatename/sandbox") in order to prevent the categories from applying to the sandbox page:

<includeonly>{{sandbox other||
[[Category:Example category]]
[[Category:Example category 2]]
}}</includeonly>

Finally, publish the page.

You can now add and edit the template data on the documentation subpage using the instructions described in #Methods.

Adding and editing template data on the main template page

If you can't create the /doc page, you can add and edit template data on the template's main page by following the instructions in #Methods.

If a template has a documentation subpage, check both the main page and the documentation subpage for the presence of template data (the ‎<templatedata> tag followed by an array inside curly brackets: {}).

Alternatively, the TemplateData extension can perform this check for you. Click "Edit" or "Edit source" on either page. If the template already has template data on either page, you will see a yellow notice at the top of the page saying either:

Please note: there is already a template data block on the related page "Template:Templatename/doc".

or

Please note: there is already a template data block on the related page "Template:Templatename".

If the template has template data on its documentation subpage

If the template has template data on its documentation subpage, this is the page you should edit. You can do this by clicking the "[edit]" located after the heading " Template documentation" (or similar), or, if you are already on the /doc page, by clicking "Edit" or "Edit source" at the top. Follow the guidance at #Methods to add or edit the template data.

If the template has template data on its main page

If the template has template data on its main page, you once again have two options:

• You can either move to its documentation subpage. This is the preferred option.

• Or, you can edit it on the main template page.

Moving template data to the documentation subpage

To do this, click "Edit"/"Edit source" on the main template page, and look for the ‎<templatedata> tags, enclosed within ‎<noinclude> tags. It should look something like this:

<noinclude>
{{Documentation}}
<templatedata>
{
    "description": "",
    "params": {
        "1": {
            "label": "Example parameter",
            "description": "Example parameter description",
            "type": "string"
        }
    }
}
</templatedata>
</noinclude>

Cut only the ‎<templatedata> tags and their contents out of the code, then save the page.

Next, edit the documentation subpage by clicking the "[edit]" located after the heading " Template documentation" (or similar).

Type a heading, like "Template data", then beneath it paste the template data.

You can now edit the template data based on the guidance at #Methods.

Editing template data on the main template page

If you do not wish to move the template data to the /doc page, you can edit it on the main template page. See #Methods for how to edit template data.

If the template does not yet have template data but has a doc subpage

If the template does not yet have template data, you should add it to the documentation subpage.

Do this by clicking the "[edit]" located after the heading " Template documentation" (or similar), or, if you are already on the /doc page, by clicking "Edit" or "Edit source" at the top. Type a heading, like "Template data", then add it beneath this heading. The section #Methods explains how to add template data.

Methods

Template data editor method

This is a simple way to add or edit template data, recommended for less experienced users.

The template data editor is a graphical user interface for adding and editing template data. It is part of the TemplateData extension, available on any template's page (or documentation subpage) by clicking "Edit" or "Edit source".

After clicking "Edit" or "Edit source", you will see a button above the editing area and page title that says "Edit template data".

Clicking this button will take you to the template data editor. If the page you are on already contains template data, it will automatically appear here.

Features in the above window:

• The top item chooses the language of the interface text. It allows you to enter text content in multiple languages, displayed to users based on their settings in Preferences, not based on the wiki's language; different wikis have entirely different template databases. If no language template data exists, the interface will only offer users the wiki's own language, but users can click "Add language" to add more inputs. The language code is displayed in brackets next to the parameters to which it can be applied, such as descriptions and labels.
• The next item is the template description. This is the description of the template as a whole; it's shown to users in numerous places in the template editors while adding a template. This parameter and its effects are documented below.
• The third item controls the wikitext formatting of the template. This parameter determines how the wikitext will be laid out when the user clicks "Apply", the two main types being "inline" (on one line) and "block" (on new lines). This parameter and its effects are documented below.

If the user chooses "Custom", they can enter wikitext under "Custom format string" according to Custom formats rules documented below, in order to create a custom layout for the template when the user clicks "Apply".

• The fourth item configures a template's parameters. If parameters have already been defined in template data, this area displays them in a list. If the template's source code specifies parameters for which no template data exists, you may see a button labeled "Add 2 suggested parameters". The editor extracts these suggestions from the template's source code by looking for {{{parametername}}} or {{{parametername|}}}. Clicking "Add 2 suggested parameters" will add these parameters using their names as defined in the source code. A green notice will also appear at the top, for example, "2 new parameters were imported: names of parameters".
• At the bottom of the window you see an "Add parameter" button. This allows you to add a parameter manually with a custom name.

Continue to the next step by clicking any one of the parameters in the list. This will allow you to edit that parameter's info.

All of these features and their effects are outlined in the section #Within a parameter's name.

* The template data editor will not allow you to change a parameter to a blank "Name". Parameters in template data that somehow acquire blank strings as names will not cause issues in the 2010 wikitext editor with TemplateWizard, but neither the visual editor nor the 2017 wikitext editor will display them at all. This is the only mandatory field in the template data editor.

• Clicking "Remove parameter information" will delete the parameter and all its information from the template data. You can't retrieve or undo this in the template data unless you click "X" afterwards. You can undo any changes made after clicking "Apply" by hitting Ctrl+Z.
• Exiting the template data editor after making changes prompts you to confirm that you want to discard your changes.

When finished, click "Apply". This will automatically insert the template data at the bottom of the page before the ‎</noinclude> tag; or, if already present, it will be updated with the new information without changing its position. The template data text will also be selected when you click "Apply".

The template data editor creates a "paramOrder" parameter at the bottom of the template data (or updates it if it already exists). "paramOrder" contains the current template data parameters in the order in which they were displayed by the template data editor. You can change the "paramOrder" by dragging the parameters up and down in the template data editor using the three horizontal bars on the left. "paramOrder" and its effects are documented below.

After this, click "Save" to save your revision of the page.

Manual method

You can also add or edit template data manually. Template data is written in JSON, but you do not need to learn JSON to learn how to create template data. Template data follows a few very simple rules and accepts only a few dozen possible predefined parameters and values, typically following a "parameter": "value" format.

Adding template data manually

Considerations:

• If you're adding template data on a template's documentation subpage (recommended), you may add it anywhere on the page; check to see if your language's Wikipedia has a preferred location for it. For example, on the English Wikipedia, template data is typically near the bottom of the documentation page; on the German Wikipedia, it is typically at the top.
• If you're adding template data on a template's main page (not recommended; see #Prior checks), you must make sure to place it inside the ‎<noinclude>...‎</noinclude> tags.

Click "Edit" or "Edit source" on the respective page, then move to the place in the page where you intend to add template data and write a heading: "Template data".

Many wikis have a {{TemplateData header }} template that adds a short notice regarding template data. If your wiki does, add it after the heading.

To start adding template data, type an opening and closing ‎<templatedata> tag and a pair of curly brackets on new lines, with an empty line between them:

<templatedata>
{

}
</templatedata>

Next, add an indent on the empty line between the two curly brackets, and start adding parameters. Details for the parameters can be found at #Template data parameters. Most are optional; some are highly recommended.

Parameters can be in any order, but what follows is the order that best conforms to template data documentation and makes the content easiest to use for editors:

<templatedata>
{
    "description": "",
    "format": "",
    "params": {
        "parameter1": {
            "aliases": ["",""]
            "label": "",
            "description": "",
            "type": ""
        }
    },
    "paramOrder": [
    	""
    ]
}
</templatedata>

Make sure the parameters, for example, in the "params" object, remain inside that object; otherwise you will trigger an "Unexpected property "propertyname"." error when you try to save.

Example

Here is some example template data for a hypothetical cleanup template. Such a template would display a notice and place the page into a dated category based on the month and year entered. The notice might also contain a link to a talk page section. The template data would look something like this:

<templatedata>
{
	"description": "Use this template to indicate that an article is in need of cleanup.",
	"format": "inline",
	"params": {
		"date": {
			"label": "Month and year",
			"description": "The month and year that the template was added",
			"type": "string",
			"autovalue": "{{SUBST:CURRENTMONTHNAME}} {{SUBST:CURRENTYEAR}}",
			"example": "January 2013",
			"suggested": true
		},
		"reason": {
			"aliases": ["1"],
			"label": "Reason",
			"description": "The reason the article is in need of cleanup",
			"type": "string"
		},
		"talk": {
			"aliases": ["talksection"],
			"label": "Talk page section",
			"description": "The section of the talk page containing relevant discussion",
			"type": "string"
		}
	},
	"paramOrder": [
		"date",
		"reason",
        "talk"
	]
}
</templatedata>

The corresponding template data documentation would display as follows:

Use this template to indicate that an article is in need of cleanup.

Template parameters

This template prefers inline formatting of parameters.

Parameter		Description	Type	Status
Month and year	date	The month and year that the template was added Example January 2013 Auto value {{SUBST:CURRENTMONTHNAME}} {{SUBST:CURRENTYEAR}}	String	suggested
Reason	reason 1	The reason the article is in need of cleanup	String	optional
Talk page section	talk talksection	The section of the talk page containing relevant discussion	String	optional

Template data parameters

All available template data parameters are listed below with a description and example. They are also listed in more technical detail at Extension:TemplateData#Format.

• This information is current as of November 2021 and may change if new parameters are added or the template editing interfaces get updates to support existing parameters or treat certain parameters differently.
• Wiki markup will not work in descriptions or labels. They are strictly plain text strings.
• New lines ("\n") in descriptions, labels, examples or defaults will not show in any of the main editors (TemplateWizard, the visual editor or the 2017 wikitext editor), even though they show in the auto-generated template data documentation. They are replaced by a null string in input forms and by a space elsewhere.

Parameter	Description	Example
description	The "description" parameter describes what the template does. It is optional but highly recommended. Effects On the template documentation page, the description will show in plain text below the "Template data for [template name]" subheading. In all main editors (VisualEditor , the 2017 wikitext editor and the WikiEditor with TemplateWizard), the description shows in two main instances: below the template name in each search suggestion when the user is searching for a template below the template name in the template editor, while they are adding values to parameters in the template. In the visual editor and 2017 wikitext editor, the description gets truncated to about 50 characters under each search suggestion, followed by a "...", but the whole description shows in the main template editor window. Both are shown in grey text. In the main template editor window, descriptions longer than four lines (about 540 characters) are provided a separate scrollbar, and they are shown in black text. If not specified If the description parameter does not exist or is not specified, the text "No description." will be displayed in the template data documentation below the "Template data for [template name]" subheading. Additionally: in the visual editor and the 2017 wikitext editor, it will behave the same as a template that does not have template data; instead of a description, the following text will display: "The "Template:Templatename" template doesn't yet have a description, but there might be some information on the template's page." in the 2010 wikitext editor with TemplateWizard, the following text will display where the description would be (except in search suggestions): "No description exists for this template." This is different from the two standard placeholder descriptions in cases when template data doesn't exist: "Due to missing template data, parameters for this template have been auto-generated. Please be aware that they may not be accurate." "No parameters could be determined for this template due to absence of template data documentation. You may insert the template without parameters."	"description": "A template for linking to a commons category",
format	The "format" parameter describes how the template's wikitext should be laid out. This can be set to the standard formats of "inline" and "block", or the user can input a set of wikitext symbols to create a custom format; these symbols and some examples are listed in the section #Custom formats. This parameter is not required, but it is recommended. The default behavior when this parameter is not provided is preserving the existing formatting for existing parameters, or inline formatting for newly added parameters and templates. Effects Inline: ("inline") When inserted, the template will lay its wikitext out on a single line with no white space between elements, like so: {{Foo|bar=baz|longparameter=quux}} Block: ("block") When inserted, the template will distribute its parameters each on a new line, with single spaces between each element, like so: {{Foo | bar = baz | longparameter = quux }} Custom formatting: Alternatively, if the parameter is set to a custom string of wikitext, as per the rules listed at #Custom formats, the template will lay its wikitext out as per the given wikitext.	"format": "inline"
params	The "params" object contains the information for each parameter of the template. It is required, and its parameters can be viewed in the #Within params section. It should contain the name of each parameter followed by a set of template data sub-parameters listed in #Within a parameter's name. If there are multiple parameters, place a comma between each parameter object, but do not add one after the last curly bracket (see example).	"params": { "parameter1": { ... // parameter info }, // comma here "parameter2": { ... // parameter info }, // and here "parameter3": { ... // parameter info } // but not here }
paramOrder	The "paramOrder" object is an optional object that causes the parameters of a template to be displayed in a specific order when added in the template editor. How to use Add the parameter "paramOrder", followed by a colon, a space and an open square bracket, then type the name of each of the template's parameters in double quotation marks (") in the desired order, separated by commas. End with a closed square bracket (creating an array). The parameters need not be on new lines (they may be written as "paramOrder": ["param1","param2","param3"]), but placing them on new lines often helps readability. We recommend you place "paramOrder" after "params", as the template data editor does; it isn't displayed in the template data documentation but simply forces the order of the parameters. A future editor may wish to quickly look through the parameter details and edit them rather than scrolling past the "paramOrder", especially if there are a lot of parameters. If you do choose to place paramOrder somewhere besides the end of the template data, end it with a comma. You must include every parameter mentioned in the template data; otherwise a "Required property "propertyname" not found." error will show. If not specified Without "paramOrder", the template's parameters will display in the order in which the template's source code declares them. If the source code contains objects inside objects, the parameters in outer objects will come first, followed by inner objects. With other parameters In the 2010 wikitext editor with TemplateWizard: "required" parameters always appear at the top, regardless of the order in "paramOrder". "suggested" parameters will always appear second, above "optional" ones. "deprecated" parameters won't appear at all in this editor; see the description of "deprecated" for more info. "paramOrder" will only enforce its order within these categories (i.e., all "required" parameters will be in the order specified by "paramOrder", and all "suggested" parameters will be too, but all "suggested" parameters will appear below all "required" parameters). In the visual editor and the 2017 wikitext editor, "paramOrder" forces its order regardless of the status of each parameter.	"paramOrder": [ "date", "reason", "talk" ]

Within params

Parameter	Description	Example
Parameter name	The only first-level item of the params object is the name of a parameter of the template. For example, in a template's source code, {{{date}}} denotes a parameter, and it should be added under "params" with the name "date". You may also see parameters named {{{1}}} or another number (whose template data name should be, for example, "1"). Parameters like this prevent a user inserting a template from having to type the parameter name and the equals sign (i.e., |value| instead of |parametername=value|). When there are multiple unnamed parameters, the number identifies which unnamed parameter is being referred to. For example, in: {{example template|value1|value2}} value1 is the value of parameter {{{1}}}, and value2 is the value of parameter {{{2}}}. Describe your template data parameters accordingly. Note: a user can still force the use of {{{2}}} without {{{1}}} by inserting a parameter named "2" in the template editor or typing "|2=" in wikitext. Finally, note that "aliases" creates alternatives to the parameter name which can be used interchangeably, and "label" replaces the parameter name in the user interface with the specified label (for situations in which the parameter name is not human readable or easily understood). How to use Each of these "Parameter name" objects should contain all of the information about the parameter, in the form of more template data parameters. These are listed in the following section, Within a parameter's name.	"1": { // name of the parameter ... // information about the parameter goes here }

Within a parameter's name

Parameter	Description	Example
aliases	The optional "aliases" parameter allows a template parameter to have multiple names. You can check this by going into the template's source code and looking for: {{{parameter1|{{{parameter2}}}}}} or {{{parameter1|{{{parameter2|}}}}}} This means that if the user inserts either of these parameters with a value, they will perform the same function. Literally, it translates to, "Value of parameter1. If parameter1 doesn't exist or have a value: value of parameter2." In the second case, it also means, "If parameter2 doesn't exist or have a value: no value." To insert the "aliases" parameter, add the text "aliases" followed by a colon, a space and an open square bracket, then typing the name of each of the parameter's aliases in quotation marks, separated by commas. End with a closed square bracket, creating an array.	"aliases": ["1", "talk", "talksection"],
inherits	"inherits" is an optional parameter for when a parameter should inherit all of the template data of another parameter. This can then be overridden by any parameters specified for the inheriting parameter. To use this parameter, type "inherits" : followed by another template parameter's name, such as "talk" or "1". You can then type another specific setting for the parameter underneath if you wish, like "label" : "A different label". The first parameter will inherit all of the second parameter's properties except this one.	"params": { "topic1": { "label": "Topic", "description": "A topic mentioned on this disambiguation page", "type": "string" }, "topic2": { "inherits": "topic1" }, "topic3": { "inherits": "topic1", "label" : "A different label" } }
label	The "label" parameter is a human-readable title for the parameter that will be displayed within the template editor. The label is displayed in place of the parameter's raw name at all times, including when an alias is used in the wikitext. This parameter is optional but highly recommended.	"label": "Month and year",
description	Here, "description" is a description of the parameter, not the template as a whole. This description appears below the parameter name (a long descriptions will be shortened with a button to optionally expand it). It is optional but highly recommended.	"description": "The month and year that the template was inserted",
type	See the #Type parameter section.
default	Some template parameters have a default value; the value is used unless overridden by the user. The "default" item is an optional item, documentary only, that is intended to communicate this default value to the user. The value need not match the actual default (if there is one) and has no functional effect. (Not to be confused with "autovalue", which is a functional parameter that fills in a field for the user.) Effects In all main editors (the visual editor, the 2017 wikitext editor and the 2010 wikitext editor with TemplateWizard), the "default" text will show as grey text in the input box of any open parameter when it is empty, in the format "Default: default text". Additionally, it will show in plain black text in the parameter description (when the user hovers over the "i" symbol). In the visual editor and the 2017 wikitext editor, this will be below the parameter description, below "Field is required"/"Field is deprecated", if specified (the 2010 wikitext editor doesn't show this text), and above "example", if specified ("example" does not show in the parameter description in the 2010 wikitext editor). In the 2010 wikitext editor with TemplateWizard, the "default" text shows directly after the parameter description, on the same line, following a space. It shows in the same format as the other editors ("Default: default text"). With other parameters In all main editors (the visual editor, the 2017 wikitext editor and the 2010 wikitext editor with TemplateWizard), if "default" is specified, the "example" value will not show in the input box.	"default": "Category:CommonsRoot",
autovalue	A parameter can be assigned an "autovalue". When a user adds the template to a page, this value will automatically appear in the input box. For example, many cleanup templates need the date added; setting the "autovalue" for the template's date parameter to be {{subst:CURRENTMONTHNAME}} {{subst:CURRENTYEAR}}, the month and year that the template was added will be filled in automatically. This value can be overwritten by the user in the template editor. With other parameters In all main editors (the visual editor, the 2017 wikitext editor and the 2010 wikitext editor with TemplateWizard), "autovalue" overrides the visible effects of "url" in the visual editor and the 2017 wikitext editor. See the description for "type" for more info.	"autovalue": "{{subst:CURRENTMONTHNAME}} {{subst:CURRENTYEAR}}"
example	The "example" parameter is optional and documentary only; its value contains an example that helps the template's user understand the correct way to fill in the parameter (not to be confused with "suggested"; see that entry for more information). Effects In all main editors (the visual editor, the 2017 wikitext editor and the 2010 wikitext editor with TemplateWizard), this property is displayed below the parameter description (and below the "default" text, if specified). With other parameters In all main editors (the visual editor, the 2017 wikitext editor and the 2010 wikitext editor with TemplateWizard), "example" will not show in the input box if "default" is specified.	"example": "January 2013",
suggested values	The parameter property suggestedvalues lets you define a list of parameter values to be shown to visual editor users in a dropdown for easy selection. This can be done either directly in JSON or using the template data editor (no coding required). You can add suggested values to be displayed in the visual editor for parameters which have their type set to one of the following options (reference): Content Line String Number Unknown Unbalanced wikitext Other types (file, page, template, user, date, boolean, URL) are not currently supported because they have special functionalities in the visual editor already, such as autocomplete, which would interfere with the drop-down menu for suggested values in the visual editor. Editing template data as JSON in wikitext To add suggested values to any parameter type, add the new property "suggestedvalues" to the parameter in JSON. The “suggestedvalues” attribute must be a list of strings. Editing template data with the template data editor Click on "Edit template data". Click on the name of the parameter you want to add suggested values to. If it’s not already done, set parameter type to one of the following: content, line, string, number, unknown, unbalanced wikitext. A new input field "Suggested values" will appear. If the parameter is already set to one of these types, the input field should already be visible. Type in the suggested value(s), including any spaces and special characters, and press enter to add the value(s) to the list. Effects Once the values have been added to template data, the visual editor will display them in a combo box (a dropdown into which users can also enter a custom value) for the parameter types listed above. The user selects the desired value by clicking on it. If the list of values is long -- for example, a list of a country’s states -- the user can begin typing in the field, whereupon the list will be filtered to show only values containing the typed text. To change an entered value, the user must simply clear the field, and the full dropdown list will appear again. If the user needs a value not included in the list (for example, "message in a bottle") they can type it in manually.	"suggestedvalues": [ "Journal", "Book", "Newspaper", "Magazine" ]

Status option	Description	Example
required	The "required" parameter can be set to either true or false. When unspecified the value defaults to false. It determines whether filling in the given parameter is mandatory for the template. Effects This status has several effects in the visual editor and the 2017 wikitext editor : it displays the parameter automatically when a user inserts the template; it shows a black asterisk within the input box, on the right; it shows the grey, italic text "Field is required." below the parameter description; it makes the input box glow red if the user clicks away without entering a value; if a user attempts to insert the template without a value in the required parameter, it will show them a prompt, asking if they are sure. If they confirm, it will insert the parameter with a blank value. It will not stop them from inserting the template, though, and it does not result in a visible error by itself (though templates can be programmed to display an error when a required parameter is not filled in). In the WikiEditor with Extension:TemplateWizard , as in the other editors, it displays the parameter automatically when a user inserts the template, but the parameter cannot be removed using this or any editor. It also does not display "Field is required." in the parameter description; rather, it lists the parameter on the side under "Required parameters". Other than this, it generally behaves the same as in the other editors, except that the prompt says that the input doesn't "match the expected format". With other parameters In the visual editor and the 2017 wikitext editor, the "deprecated" status does not override the functionality of this parameter, but in the 2010 wikitext editor with TemplateWizard it does. See the description of "deprecated" for more info.	"required": true
suggested	The "suggested" parameter can be set to either true or false. When unspecified it defaults to false. Use "suggested" for parameters that are not mandatory but strongly recommended for template users to provide. When filling in this parameter, a user will see this suggestion. Effects In the visual editor and the 2017 wikitext editor , it causes the parameter to automatically show up when a user inserts a template. If the parameter has an autovalue set, this will also automatically be in the parameter's input box. It has no other effect and doesn't show any additional text or warnings. In the WikiEditor with TemplateWizard, it does not place the parameter in the template automatically but instead causes it to be listed on the side under "Suggested parameters". The user can then click a "+" next to the parameter to add it to the template. With other parameters The "required" status overrides the functionality of this status in all main editors (the visual editor, the 2017 wikitext editor and the 2010 wikitext editor). It also overrides the displayed "suggested" status in template data documentation (it will display "required" if both "required" and "suggested" are set to true).	"suggested": true
deprecated	Finally, there is "deprecated", which can be set to true, false, or a string describing what users should instead do. When unspecified it defaults to false. This is a status for parameters that should not be used any more but still exist for the time being. This could be because uses of the template are being moved from one set of parameters to another. Effects The effect of this parameter in the visual editor and the 2017 wikitext editor is that a grey exclamation mark shows next to the parameter's label when it is inserted, and in the parameter's information tooltip, the grey, italic text "Field is deprecated. deprecation reason" is shown below the parameter description. It does not affect the functionality or usability of the parameter or show any additional warnings. Despite the fact that it can take a string, as of January 2020 none of the main editors (the visual editor, the 2017 wikitext editor or the 2010 wikitext editor) display the contents of the string anywhere to users. Inputting a string has the same effect as true. In the 2010 wikitext editor with TemplateWizard, setting this value as true does not allow the parameter to be added or seen. With other parameters If you set both this and "suggested" as true, the parameter status will show as "deprecated" in the template data documentation, but in the visual editor and the 2017 wikitext editor both functionalities will be retained; the parameter will automatically show up when a user inserts a template, but it will have the "deprecated" warnings around it. If you set both this and "required" as true, the parameter status will show as "deprecated" in the template data documentation, but in the visual editor and the 2017 wikitext editor it will have the same functionality as only "required"; the parameter will automatically show up when a user inserts a template, and it will have the "required" warnings around it. This is the same for if you set "deprecated", "suggested" and "required" as true. In the 2010 wikitext editor with TemplateWizard, "deprecated" overrides the parameters "required" and "suggested".	"deprecated": "Please use 'publicationDate' instead."

Note: if neither "required", "suggested" nor "deprecated" are set as true for a parameter, its status will show as "optional" in the template data documentation.

Once you're done, hit "Save". If you've made errors, it will not let you save (which is disruptive but means you can't break anything). Should you run into errors, explain on the feedback page what you were trying to do, and we will be happy to help.

Note that if you are abusing a hack template to dynamically generate template data, it cannot be checked for errors before saving.

Note that each item of information is enclosed in quotation marks (except for true and false) and separated from the next item by a comma (unless it's the last one).

Type parameter

The "type" parameter is meant to signal to a template editor the nature of a parameter's value. In some cases, template editors have been programmed to modify the user interface for a certain parameter according to this template data value, such as to only allow the user to enter valid values that match the specified type. This parameter does not have any functional effect on the template parameter or its value; it merely controls how template editors see and treat the parameter in editing mode.

How to use

It is used by adding the "type" parameter, followed by a colon and a space, then adding any of the values listed in the table below in quotation marks.

Example:

"type": "string",

Effects

As of February 2020, only 5 of the 13 type values have visible effects in VisualEditor and the 2017 wikitext editor, while 8 have visible effects in TemplateWizard.

The effects of certain values are likely to change as the template editors get updates to support them. One such effort for VisualEditor and the 2017 wikitext editor is tracked in the Phabricator task T55613. A similar effort to get TemplateWizard to support the boolean value is tracked in T200664.

The currently known effects are listed as follows.

Value	Description
unknown	The "unknown" value is the default type value if no type is set. It can also be set manually by typing "type": "unknown". Effects In all main editors (VisualEditor, 2017 wikitext editor and the 2010 wikitext editor with TemplateWizard), "unknown" has no visible effects compared to a template without template data.
string	The "string" value is intended for any string of plain text. Effects In all main editors (the visual editor, the 2017 wikitext editor and the 2010 wikitext editor with TemplateWizard), "string" has no visible effect compared to "unknown".
line	The "line" value is intended for content that should be forced to stay on one line. Effects In the visual editor and the 2017 wikitext editor, "line" prevents a parameter's input box from allowing new lines, which are usually possible in these editors. In the 2010 wikitext editor with TemplateWizard, "line" has no visible effect (input boxes do not allow new lines by default in this editor).
content	The "content" value is intended for wikitext of page content, for example, links, images or text formatting. Effects In the visual editor and the 2017 wikitext editor, "content" has no visible effect. In the 2010 wikitext editor with TemplateWizard, "content" makes the parameter input box one line taller and allows new lines, which regular input boxes in the 2010 wikitext editor do not.
unbalanced-wikitext	The "unbalanced-wikitext" value is intended for wikitext that cannot stand alone, i.e. it lacks an opening or closing tag or refers to other parts of wikitext. Effects In the visual editor and the 2017 wikitext editor, "unbalanced-wikitext" has no visible effect. In the 2010 wikitext editor with TemplateWizard, "unbalanced-wikitext" makes the parameter input box one line taller and allows new lines, which regular input boxes in the 2010 wikitext editor do not.
wiki-page-name	The "wiki-page-name" value is intended for a page name on a wiki. Effects In all main editors (the visual editor, the 2017 wikitext editor and the 2010 wikitext editor with TemplateWizard), "wiki-page-name" makes the parameter input box show a suggestion dropdown menu containing a list of pages on the wiki, such as articles on Wikipedia, which can be selected. Namespaces can also be defined in the search. Additionally, in the visual editor and the 2017 wikitext editor, it forces the input box content to stay on one line. It has no other visible effect and doesn't prevent a non-page from being inputted.
wiki-file-name	The "wiki-file-name" value is intended for a file name hosted either locally on a wiki or on Wikimedia Commons. Effects In the visual editor and the 2017 wikitext editor, "wiki-file-name" has no visible effect. In the 2010 wikitext editor with TemplateWizard, "wiki-file-name" makes the parameter input box show a suggestion dropdown menu containing a list of files hosted both locally and on Wikimedia Commons, which can be selected. The file names do not contain the "File:" namespace prefix. The dropdown menu also shows the thumbnail of the files. It has no other visible effect and doesn't prevent a non-file from being inputted.
wiki-template-name	The "wiki-template-name" value is intended for the name of a template. Effects In all main editors (the visual editor, the 2017 wikitext editor and the 2010 wikitext editor with TemplateWizard), "wiki-template-name" makes the parameter input box show a suggestion dropdown menu containing a list of templates, which can be selected. Additionally, in the visual editor and the 2017 wikitext editor, it forces the input box content to stay on one line. It has no other visible effect and doesn't prevent a non-template from being inputted.
wiki-user-name	The "wiki-user-name" value is intended for a username on a wiki. Effects In all main editors (the visual editor, the 2017 wikitext editor and the 2010 wikitext editor with TemplateWizard), "wiki-user-name" makes the parameter input box show a suggestion dropdown menu containing a list of actual users' names, which can be selected. Additionally, in the visual editor and the 2017 wikitext editor, it forces the input box content to stay on one line. It has no other visible effect and doesn't prevent a non-username from being inputted.
number	The "number" value is intended for numerical values, including negative values and decimals. Effects In the visual editor and the 2017 wikitext editor, "number" has no visible effect. In the 2010 wikitext editor with TemplateWizard, "number" causes the input box to display a "+" and "-" button on either side, which can raise or lower a number value in the input box, and the user can only type numbers into the box. The buttons can also lower the number into negatives. With other parameters In the 2010 wikitext editor with TemplateWizard, "number" overrides the effects of "autovalue"; the value of "autovalue" will not be automatically placed in the input box if the parameter type is "number".
boolean	The "boolean" value is intended for a value that is either true, false or unknown. This is intended by the manual to be represented by a "1", "0" or blank value. Effects As of February 2020, none of the main Wikimedia editors (the visual editor, the 2017 wikitext editor or the 2010 wikitext editor with TemplateWizard) make use of this value. It has no visible effects. With the autovalue:0 checkbox appears in the visual editor, which can be switched on and off.
date	The "date" value is intended for a date in the YYYY-MM-DD (ISO 8601) format; for example, 2014-05-22. The template data manual also designates it as being intended for ISO 8601 date–time combinations, such as "2014-05-22T16:01:12Z", but in practice no major editing interface as of February 2020 uses it in this fashion, and almost all major Wikimedia template parameters take dates and times separately. Effects In the visual editor and the 2017 wikitext editor, "date" has no visible effect. In the 2010 wikitext editor with TemplateWizard, "date" makes the parameter input box about a third shorter and adds a dropdown calendar, allowing the user to choose a date input. It also displays the grey example text in the input box "YYYY-MM-DD". If an input does not conform to this standard, the box glows red, however the editor will always output a date conforming to the standard (if numbers are entered) or nothing (if only text or nothing is entered). With other parameters In the 2010 wikitext editor with TemplateWizard, "date" overrides the effects of "autovalue"; the value of "autovalue" will not be automatically placed in the input box if the parameter type is "date".
url	The "url" value is intended for a URL, with Internet protocol (e.g., "https://" or "//") included. Effects In the visual editor and the 2017 wikitext editor, "url" makes the input box display an external link icon (a square with arrow pointing out of it) in the left hand side of the box and makes the box glow red when the user clicks away without entering a URL value that includes a valid Internet protocol (e.g., "https://", "ftp://" or "//") followed by some text. This second effect is similar to that of the "required" setting, but it does not warn the user if they attempt to insert the template without a valid URL. It also occurs with any status setting (such as "suggested"" or "deprecated"). In the 2010 wikitext editor with TemplateWizard, "url" has no visible effect. With other parameters In the visual editor and the 2017 wikitext editor, "autovalue" overrides the visible effects of "url": when both are set, the input box will not contain a URL icon nor glow red when the user clicks away without entering a valid URL.

Custom formats

When editing the "format" value, you create custom formats by inputting a set of wikitext symbols using some predefined rules.

• {{ - start of the template
• _ - content (e.g., string, integer or parameter). This underscore serves to indicate the minimum length of a value in characters and can be repeated, like _______. If this length is not reached, it fills the remaining characters with spaces. This can be used to align all equals signs to a specific position after a parameter (if used with \n for new lines).
• | - pipe (separates parameters)
• = - equals sign (precedes the value of a parameter)
• \n or pressing the enter key - new line (this will display as ↵ in the entry field)
• - space (can be used with \n to indent new lines)
• }} - end of the template

The wikitext should at least meet the minimum of {{_|_=_}}, otherwise there will be an invalid format string error.

Examples of formats you can use

Objective	Format string	Output
Inline formatting	{{_|_=_}} inline	{{Foo|bar=baz|longparameter=quux}}{{Bar}}
Block formatting	{{_\n| _ = _\n}} block	{{Foo | bar = baz | longparameter = quux }}{{Bar}}
No space before the parameter name, each template on its own line	\n{{_\n|_ = _\n}}\n	{{Foo |bar = baz |longparameter = quux }} {{Bar}}
Indent each parameter	{{_\n |_ = _\n}}	{{Foo |bar = baz |longparameter = quux }}{{Bar}}
Align all parameter names to a given length	{{_\n|_______________ = _\n}}\n	{{Foo |bar = baz |longparameter = quux |veryverylongparameter = bat }} {{Bar}}
Pipe characters at the end of the previous line	{{_|\n _______________ = _}}	{{Foo| bar = baz| longparameter = quux}}{{Bar}}
Inline style with more spaces, must be at start of line	\n{{_ | _ = _}}	{{Foo | bar = baz | longparameter = quux}} {{Bar }}
Template at the start of a line, indent-aligned parameters, pipe beforehand	\n{{_ |\n _______________ = _}}	{{Foo | bar = baz | longparameter = quux}} {{Bar}}

Blank boilerplate

You can copy the blank boilerplate below to add new template data to a template. Only the most common tags are included.

<templatedata>
{
    "description": "",
    "params": {
        "1": {
            "label": "",
            "description": "",
            "type": ""
        },
        "2": {
            "label": "",
            "description": "",
            "type": ""
        }
    }
}
</templatedata>

Errors

Syntax error in JSON. / Bad JSON format

These errors occur when saving template data, usually manually edited, with invalid JSON code (duplicate keys/parameters, trailing or missing commas, etc.) in the visual editor or the 2017 wikitext editor.

"Syntax error in JSON." appears in the visual editor and the 2017 wikitext editor; "Bad JSON format" appears when editing in the template data GUI editor.

These errors can be difficult to detect and come in too many forms to list. The best way to avoid them is to edit template data exclusively with the template data editor; the best way to detect them once they've occurred is to use an external JSON validator, such as JSONLint, which will highlight errors and aid in fixing them.

The 2010 wikitext editor does not check for invalid JSON thanks to an old, unfixed bug (task T128029). Pages that contain invalid JSON may throw alarming "Internal error" messages. To fix these errors, your best bet is to use a JSON validator (see above).

Required property "paramOrder[number]" not found.

This error occurs if you state a parameter in "params" that is not stated in "paramOrder". The number in the square brackets refers to the parameter in "paramOrder" that is missing. It refers to its order in the sequence, but it is one less than its actual position, since "paramOrder" is an array; 0 is the first one, 1 is the second, etc.

"params": {
    "date": { ...
    },
    "reason": { ...
    },
    "talk": { ... // <-- This parameter is not stated in "paramOrder", but it should be.
    }
},
"paramOrder": [
	"date",
	"reason"
]

// Error: Required property "paramOrder[2]" not found.

To fix this, make sure all parameters stated in "params" are listed in "paramOrder". Alternatively, you can remove the "paramOrder" object to remove this error.

Invalid value for property "paramOrder[number]".

This error occurs if you state a parameter in "paramOrder" that is not stated in "params". The number in the square brackets refers to the parameter in "paramOrder" that shouldn't be there. It refers to its order in the sequence, but it is one less than its actual position, since "paramOrder" is an array; 0 is the first one, 1 is the second, etc.

"params": {
    "date": { ...
    },
    "talk": { ...
    }
},
"paramOrder": [
	"date",
	"reason", // <-- This parameter is not stated in "params", but it should be.
    "talk"
]

// Error: Invalid value for property "paramOrder[1]".

To fix this, make sure all parameters stated in "paramOrder" are listed in "params". Alternatively, you can remove the "paramOrder" object to remove this error.

Property "params.parametername.required" is expected to be of type "boolean".

This error occurs if you put quotation marks around the value of either "required" or "suggested".

"suggested": "true" // <-- These quotation marks shouldn't be here.

These are boolean values, not strings, therefore they require no quotation marks. To fix this, remove any quotation marks around the values true or false for these parameters.

Property "format" is expected to be ...

If the "format" parameter exists but its value is not "inline", "block" or a valid format string, you will see the error message "Property "format" is expected to be "inline", "block", or a valid format string.".

"format": "notinline"

// Error : Property "format" is expected to be "inline", "block", or a valid format string.

To fix this, make sure the value after "format": equals "inline" or "block" and that there no spelling mistakes. Alternatively, if it's wikitext, make sure it contains a minimum of {{_|_=_}} and that there are no mistakes in the syntax that would normally cause a template to fail, such as duplicate equals signs or missing/duplicate curly brackets; see the section #Custom formats for the syntax for custom formats. Alternatively, you can remove the "format" parameter to remove this error.

Unexpected property "parametername".

This error occurs if you state a parameter that is unknown in template data. This is probably due to spelling mistakes or the use of uppercase letters instead of lowercase.

<templatedata>
{
    "description": "",
    "format": "inline",
    "params": {
        "1": {
            "label": "",
            "descriptino": "", // <-- spelling mistake
            "type": ""
        }
    }
}
</templatedata>

It also occurs if you state a parameter in any template data object that is not a parameter of that object. This may be due to spelling mistakes, or you may have written the parameter of one template data object under another object that it doesn't belong to.

For example, you might have written the parameter "label" under the root template data object instead of inside "params":

<templatedata>
{
    "description": "",
    "format": "inline",
    "label": "", // <-- incorrectly placed parameter
    "params": {
        "1": { // ↓ it should be in here
            "description": "",
            "type": ""
        }
    }
}
</templatedata>

Alternatively, if the unexpected parameter is under a template parameter inside "params", you'll see its name after "params.parametername." in the error.

To fix this, make sure there aren't any spelling mistakes in the parameter names, and make sure your parameters are in their correct location. Additionally, make sure you don't state any parameters that don't exist for a template data object. You can check which parameters exist for an object in the section #Template data parameters.

Required property "params" not found.

This error occurs if there is no "params" object in the template data. This is a necessary object, as it contains all the details of each parameter, so to fix this error, make sure it's added and that there are no spelling mistakes. See the section above on how to add the "params" parameter.

Limitations and feedback

• Missing features – Template data is an example of a tool that was made available with few features, in hope that users would help to guide development of features that they desired. If you'd like to request new features for template data, please let us know.
• Delays in showing in templates – After adding template data to a template, the metadata should be visible immediately when the template is opened in the visual editor. However, it is possible that it will take several hours before the metadata will show. You can force an update by making a null edit to the template page itself (not the documentation subpage). To perform a null edit, open the template page for editing, and save the page without making any change and without adding any edit summary.
• Current issues – A list of current bugs and feature requests is available in the Wikimedia bug tracker.

Other tools

Help:Extension:TemplateWizard

A toolbar dialog window for entering template wikitext via an form built from template data.

TemplateData Wizard

A tool that generates template data through an interactive interface.

Skeleton TemplateData generator

A tool that reads the source wikicode of a template, tries to find all the parameters used and outputs a skeleton document with the parameters listed.

JSONLint

A tool that allows you to validate manually-written JSON to help find errors in the syntax.

• List of all templates with template data on this wiki
• With dewiki template template data: template data is shown in a box, and the template is added to a category of templates with template data
• https://query.wikidata.org/ and Query Helper