@gechiui/rich-text

Rich Text

This module contains helper functions to convert HTML or a DOM tree into a rich text value and back, and to modify the value with functions that are similar to String methods, plus some additional ones for formatting.

Installation

Install the module

npm install @gechiui/rich-text

This package assumes that your code will run in an ES2015+ environment. If you're using an environment that has limited or no support for such language features and APIs, you should include the polyfill shipped in @gechiui/babel-preset-default in your code.

Usage

The Rich Text package is designed to aid in the manipulation of plain text strings in order that they can represent complex formatting.

By using a RichTextValue value object (referred to from here on as value) it is possible to separate text from formatting, thereby affording the ability to easily search and manipulate rich formats.

Examples of rich formats include:

• bold, italic, superscript (etc)
• links
• underordered/ordered lists

The RichTextValue object

The value object is comprised of the following:

• text - the string of text to which rich formats are to be applied.
• formats - a sparse array of the same length as text that is filled with formats (e.g. core/link, core/bold etc.) at the positions where the text is formatted.
• start - an index in the text representing the start of the currently active selection.
• end - an index in the text representing the end of the currently active selection.

You should not attempt to create your own value objects. Rather you should rely on the built in methods of the @gechiui/rich-text package to build these for you.

It is important to understand how a value represents richly formatted text. Here is an example to illustrate.

If text is formatted from position 2-5 in bold (core/bold) and from position 2-8 with a link (core/link), then you'll find:

• arrays within the sparse array at positions 2-5 that include the core/bold format
• arrays within the sparse array at positions 2-8 that include the core/link format

Here's how that would look:

{
  text: 'Hello world', // length 11
  formats: [
    [], // 0
    [],
    [ // 2
      {
        type: 'core/bold',
      },
      {
        type: 'core/link',
      }
    ],
    [
      {
        type: 'core/bold',
      },
      {
        type: 'core/link',
      }
    ],
    [
      {
        type: 'core/bold',
      },
      {
        type: 'core/link',
      }
    ],
    [
      {
        type: 'core/bold',
      },
      {
        type: 'core/link',
      }
    ],
    [ // 6
      {
        type: 'core/link',
      }
    ]
    [
      {
        type: 'core/link',
      }
    ],
    [
      {
        type: 'core/link',
      }
    ],
    [], // 9
    [], // 10
    [], // 11
  ]
}

Selections

Let's continue to consider the above example with the text Hello world.

If, as a user, I make a selection of the word Hello this would result in a value object with start and end as 0 and 5 respectively.

In general, this is useful for knowing which portion of the text is selected. However, we need to consider that selections may also be "collapsed".

Collapsed selections

A collapsed selection is one where start and end values are identical (e.g. start: 4, end: 4). This happens when no characters are selected, but there is a caret present. This most often occurs when a user places the cursor/caret within a string of text but does not make a selection.

Given that the selection has no "range" (i.e. there is no difference between start and end indices), finding the currently selected portion of text from collapsed values can be challenging.

API

applyFormat

Apply a format object to a Rich Text value from the given startIndex to the given endIndex. Indices are retrieved from the selection if none are provided.

Parameters

• value RichTextValue: Value to modify.
• format RichTextFormat: Format to apply.
• startIndex [number]: Start index.
• endIndex [number]: End index.

Returns

• RichTextValue: A new value with the format applied.

concat

Combine all Rich Text values into one. This is similar to String.prototype.concat.

Parameters

• values ...RichTextValue: Objects to combine.

Returns

• RichTextValue: A new value combining all given records.

create

Create a RichText value from an Element tree (DOM), an HTML string or a plain text string, with optionally a Range object to set the selection. If called without any input, an empty value will be created. If multilineTag is provided, any content of direct children whose type matches multilineTag will be separated by two newlines. The optional functions can be used to filter out content.

A value will have the following shape, which you are strongly encouraged not to modify without the use of helper functions:

{
  text: string,
  formats: Array,
  replacements: Array,
  ?start: number,
  ?end: number,
}

As you can see, text and formatting are separated. text holds the text, including any replacement characters for objects and lines. formats, objects and lines are all sparse arrays of the same length as text. It holds information about the formatting at the relevant text indices. Finally start and end state which text indices are selected. They are only provided if a Range was given.

Parameters

• $1 [Object]: Optional named arguments.
• $1.element [Element]: Element to create value from.
• $1.text [string]: Text to create value from.
• $1.html [string]: HTML to create value from.
• $1.range [Range]: Range to create value from.
• $1.multilineTag [string]: Multiline tag if the structure is multiline.
• $1.multilineWrapperTags [Array]: Tags where lines can be found if nesting is possible.
• $1.preserveWhiteSpace [boolean]: Whether or not to collapse white space characters.
• $1.__unstableIsEditableTree [boolean]:

Returns

• RichTextValue: A rich text value.

getActiveFormat

Gets the format object by type at the start of the selection. This can be used to get e.g. the URL of a link format at the current selection, but also to check if a format is active at the selection. Returns undefined if there is no format at the selection.

Parameters

• value RichTextValue: Value to inspect.
• formatType string: Format type to look for.

Returns

• RichTextFormat|undefined: Active format object of the specified type, or undefined.

getActiveObject

Gets the active object, if there is any.

Parameters

• value RichTextValue: Value to inspect.

Returns

• RichTextFormat|void: Active object, or undefined.

getTextContent

Get the textual content of a Rich Text value. This is similar to Element.textContent.

Parameters

• value RichTextValue: Value to use.

Returns

• string: The text content.

insert

Insert a Rich Text value, an HTML string, or a plain text string, into a Rich Text value at the given startIndex. Any content between startIndex and endIndex will be removed. Indices are retrieved from the selection if none are provided.

Parameters

• value RichTextValue: Value to modify.
• valueToInsert RichTextValue|string: Value to insert.
• startIndex [number]: Start index.
• endIndex [number]: End index.

Returns

• RichTextValue: A new value with the value inserted.

insertObject

Insert a format as an object into a Rich Text value at the given startIndex. Any content between startIndex and endIndex will be removed. Indices are retrieved from the selection if none are provided.

Parameters

• value RichTextValue: Value to modify.
• formatToInsert RichTextFormat: Format to insert as object.
• startIndex [number]: Start index.
• endIndex [number]: End index.

Returns

• RichTextValue: A new value with the object inserted.

isCollapsed

Check if the selection of a Rich Text value is collapsed or not. Collapsed means that no characters are selected, but there is a caret present. If there is no selection, undefined will be returned. This is similar to window.getSelection().isCollapsed().

Parameters

• value RichTextValue: The rich text value to check.

Returns

• boolean|undefined: True if the selection is collapsed, false if not, undefined if there is no selection.

isEmpty

Check if a Rich Text value is Empty, meaning it contains no text or any objects (such as images).

Parameters

• value RichTextValue: Value to use.

Returns

• boolean: True if the value is empty, false if not.

join

Combine an array of Rich Text values into one, optionally separated by separator, which can be a Rich Text value, HTML string, or plain text string. This is similar to Array.prototype.join.

Parameters

• values Array<RichTextValue>: An array of values to join.
• separator [string|RichTextValue]: Separator string or value.

Returns

• RichTextValue: A new combined value.

registerFormatType

Registers a new format provided a unique name and an object defining its behavior.

Parameters

• name string: Format name.
• settings GCFormat: Format settings.

Returns

• GCFormat|undefined: The format, if it has been successfully registered; otherwise undefined.

remove

Remove content from a Rich Text value between the given startIndex and endIndex. Indices are retrieved from the selection if none are provided.

Parameters

• value RichTextValue: Value to modify.
• startIndex [number]: Start index.
• endIndex [number]: End index.

Returns

• RichTextValue: A new value with the content removed.

removeFormat

Remove any format object from a Rich Text value by type from the given startIndex to the given endIndex. Indices are retrieved from the selection if none are provided.

Parameters

• value RichTextValue: Value to modify.
• formatType string: Format type to remove.
• startIndex [number]: Start index.
• endIndex [number]: End index.

Returns

• RichTextValue: A new value with the format applied.

replace

Search a Rich Text value and replace the match(es) with replacement. This is similar to String.prototype.replace.

Parameters

• value RichTextValue: The value to modify.
• pattern RegExp|string: A RegExp object or literal. Can also be a string. It is treated as a verbatim string and is not interpreted as a regular expression. Only the first occurrence will be replaced.
• replacement Function|string: The match or matches are replaced with the specified or the value returned by the specified function.

Returns

• RichTextValue: A new value with replacements applied.

slice

Slice a Rich Text value from startIndex to endIndex. Indices are retrieved from the selection if none are provided. This is similar to String.prototype.slice.

Parameters

• value RichTextValue: Value to modify.
• startIndex [number]: Start index.
• endIndex [number]: End index.

Returns

• RichTextValue: A new extracted value.

split

Split a Rich Text value in two at the given startIndex and endIndex, or split at the given separator. This is similar to String.prototype.split. Indices are retrieved from the selection if none are provided.

Parameters

• value RichTextValue:
• string [number|string]: Start index, or string at which to split.

Returns

• Array<RichTextValue>|undefined: An array of new values.

store

Store definition for the rich-text namespace.

Related

• https://github.com/GeChiUI/gutenberg/blob/HEAD/packages/data/README.md#createReduxStore

Type

• Object

toggleFormat

Toggles a format object to a Rich Text value at the current selection.

Parameters

• value RichTextValue: Value to modify.
• format RichTextFormat: Format to apply or remove.

Returns

• RichTextValue: A new value with the format applied or removed.

toHTMLString

Create an HTML string from a Rich Text value. If a multilineTag is provided, text separated by a line separator will be wrapped in it.

Parameters

• $1 Object: Named argements.
• $1.value RichTextValue: Rich text value.
• $1.multilineTag [string]: Multiline tag.
• $1.preserveWhiteSpace [boolean]: Whether or not to use newline characters for line breaks.

Returns

• string: HTML string.

unregisterFormatType

Unregisters a format.

Parameters

• name string: Format name.

Returns

• RichTextFormatType|undefined: The previous format value, if it has been successfully unregistered; otherwise undefined.

useAnchorRef

This hook, to be used in a format type's Edit component, returns the active element that is formatted, or the selection range if no format is active. The returned value is meant to be used for positioning UI, e.g. by passing it to the Popover component.

Parameters

• $1 Object: Named parameters.
• $1.ref RefObject<HTMLElement>: React ref of the element containing the editable content.
• $1.value RichTextValue: Value to check for selection.
• $1.settings RichTextFormatType: The format type's settings.

Returns

• Element|Range: The active element or selection range.

Contributing to this package

This is an individual package that's part of the Gutenberg project. The project is organized as a monorepo. It's made up of multiple self-contained software packages, each with a specific purpose. The packages in this monorepo are published to npm and used by GeChiUI as well as other software projects.

To find out more about contributing to this package or Gutenberg as a whole, please read the project's main contributor guide.