created: 20220305183700000
modified: 20220413165500000
tags: Concepts
title: Customizing EditTemplate field rendering
type: text/vnd.tiddlywiki

When editing a tiddler the [[EditTemplate|$:/core/ui/EditTemplate/fields]] normally renders fields as simple input boxes. To modify this behaviour, the [[cascade mechanism|Cascades]] can be used. Via the [[Field Editor Cascade|Field Editor Cascade]] the name of the tiddler used for rendering the field editor can be specified. The content of this tiddler is transcluded to represent the content of the field.

To modify the appearance of all fields whose name ends with `-date` create a new tiddler and add the `$:/tags/FieldEditorFilter` tag to it. Add a `list-before` field and assign the value `$:/config/FieldEditorFilters/default`. Now you have to put the filter for the cascade into the tiddler's text field: `[suffix[-date]then[$:/config/EditTemplateFields/Templates/dates]]`. This will transclude the tiddler named `$:/config/EditTemplateFields/Templates/dates` to render the input elements for all fields with names matching the regular expression.

The variables `currentTiddler`, `currentField` and `currentFieldName` are set to pass information about the tiddler and field that are edited to the transcluded tiddler.

|`currentTiddler`|The tiddler that must be used to store the field value.|
|`currentField`|The field within the `currentTiddler` that must be used to store the field name. This is an opaque value hat may contain any field name (even `text`), use `currentFieldName` to make decisions based on the actual name of the currently edited field.|
|`currentFieldName`|The name of the currently edited field.|

For example, a tiddler containing the following WikiText would render the field as an HTML input element of the type `date`. This will show a date picker for the fields on all modern browsers:

```
<$edit-text tiddler=<<currentTiddler>> field=<<currentField>> tag="input" type="date" class="tc-edit-texteditor tc-edit-fieldeditor" placeholder="Set your date" tabindex={{$:/config/EditTabIndex}} cancelPopups="yes"/>
```

<<.warning "The `currentField` variable will be set to `text` for new fields. Make sure that your editor will handle this correctly. For example, by setting the `tag` attribute on the EditTextWidget. If you want to know the name of the currently edited/added field, use the `currentFieldName` variable.">>

The `tabindex` and `cancelPopups` attributes make sure the HTML input element behaves exactly the default elements provided by TiddlyWiki.

Not only the EditTextWidget can be used. A tiddler containing the following WikiText will render the field as a drop-down-list that allows the user to select the name of a tiddler. The name of the selected tiddler will be stored in the field.

```
<$select tiddler=<<currentTiddler>> field=<<currentField>> class="tc-edit-texteditor tc-edit-fieldeditor" cancelPopups="yes">
    <$list filter='[all[tiddlers]sort[title]]'>
        <option value=<<currentTiddler>>><$view field='title'/></option>
    </$list>
</$select>
```

The classes `tc-edit-texteditor` and `tc-edit-fieldeditor` should be used to style the `input` and `select` elements to match the theme of the TiddlyWiki installation.

! Persistence of values when creating fields

When using multiple field editors for creating fields within the [[EditTemplate|$:/core/ui/EditTemplate/fields]], every field editor tiddler returned by the [[Field Editor Cascade|Field Editor Cascade]] gets its own storage tiddler. This is done to prevent problems with incompatible values when the user is switching between fields governed by different field editors.

!! Example

There is a cascade that returns a special field editor for all fields starting with the string "my-". All other fields use the default field editor.
If you type a new value into the "field value" input box and select any field not starting with "my-", the value will be kept.
If you switch to a field, that starts with "my-", the "field value" input field will be empty again because a new type of field editor is used. If you now type a value and switch to another field starting with "my-" the value will be kept. If you switch to a field that does not start with "my-" the previously typed value (that was stored for the default editor) will reappear.