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Draft.js filters

Filter Draft.js content to preserve only the formatting you allow. Built for Draftail.

The main use case is to select what formatting to keep when copy-pasting rich text into an editor, for example from Word or Google Docs, addressing Draft.js limitations like #166 and #504. Check out the online demo!

If you want to learn more about how this is used in practice, have a look at Rethinking rich text pipelines with Draft.js.

Using the filters

First, grab the package from npm:

npm install --save draftjs-filters

Then, in your editor import filterEditorState and call it in the Draft.js onChange handler. This function takes two parameters: the filtering configuration, and the editorState.

import { filterEditorState } from "draftjs-filters"

function onChange(nextState) {
  const { editorState } = this.state
  let filteredState = nextState

  const shouldFilterPaste =
    nextState.getCurrentContent() !== editorState.getCurrentContent() &&
    nextState.getLastChangeType() === "insert-fragment"

  if (shouldFilterPaste) {
    filteredState = filterEditorState(
      {
        blocks: ["header-two", "header-three", "unordered-list-item"],
        styles: ["BOLD"],
        entities: [
          {
            type: "IMAGE",
            attributes: ["src"],
            allowlist: {
              src: "^http",
            },
          },
          {
            type: "LINK",
            attributes: ["url"],
          },
        ],
        maxNesting: 1,
        whitespacedCharacters: ["\n", "\t", "📷"],
      },
      filteredState,
    )
  }

  this.setState({ editorState: filteredState })
}

Here are all the available options:

// List of allowed block types. unstyled and atomic are always included.
blocks: readonly string[]>,
// List of allowed inline styles.
styles: readonly string[]>,
// List of allowed entities.
entities: readonly []<{
  // Entity type, eg. "LINK"
  type: string,
  // Allowed attributes. Other attributes will be removed. If this is omitted, all attributes are kept.
  attributes?: readonly string[]>,
  // Refine which entities are kept by matching acceptable values with regular expression patterns.
  // It's also possible to use "true" to signify that a field is required to be present,
  // and "false" for fields required to be absent.
  // If this is omitted, all entities are kept.
  allowlist?: {
    [attribute: string]: string | boolean,
  },
}>,
// Maximum amount of depth for lists (0 = no nesting).
maxNesting: number,
// Characters to replace with whitespace.
whitespacedCharacters: Array<string>,
// Optional: Rules used to automatically convert blocks from one type to another
// based on the block’s text. Also supports setting the block depth.
// Defaults to the filters’ built-in block prefix rules.
blockTextRules?: readonly []<{
  // A regex as a string, to match against block text, e.g. "^(◦|o |o\t)".
  test: string,
  // The type to convert the block to if the test regex matches.
  type: string,
  // The depth to set (e.g. for list items with different prefixes per depth).
  depth: number,
}>,

Deprecated

filterEditorState (and shouldKeepEntityByAttribute described further below) used to support a whitelist config option. It has been renamed to allowlist, and will be removed altogether in a future release.

Types

If your project uses TypeScript, type inference should just work. If you don't use TypeScript, it won't get in your way either.

Flow types were included up to v2.5.0 of the package, and have been removed in v3.0.0. They may still be used by manually downloading the library definitions and manually adding them to projects.

Advanced usage

filterEditorState isn't very flexible. If you want more control over the filtering, simply compose your own filter function with the other single-purpose utilities. The Draft.js filters are published as ES6 modules using Rollup – module bundlers like Rollup and Webpack will tree shake (remove) the unused functions so you only bundle the code you use.

If using filters that remove blocks, be sure to use applyContentWithSelection to restore the selection where appropriate after filtering.

API

preserveAtomicBlocks

Creates atomic blocks where they would be required for a block-level entity to work correctly, when such an entity exists. Note: at the moment, this is only useful for IMAGE entities that Draft.js injects on arbitrary blocks on paste.

Parameters
  • content ContentState
resetAtomicBlocks

Resets atomic blocks to have a single-space char and no styles. This is how they are stored by Draft.js by default.

Parameters
  • content ContentState
removeInvalidAtomicBlocks

Removes atomic blocks for which the entity type isn't allowed.

Parameters
  • allowlist readonly {type: string}[]
  • content ContentState
removeInvalidDepthBlocks

Removes blocks that have a non-zero depth, and aren't list items. Happens with Apple Pages inserting unstyled items between list items.

Parameters
  • content ContentState
preserveBlockByText

Changes block type and depth based on the block's text. – some word processors add a specific prefix within the text, eg. "· Bulleted list" in Word 2010. Also removes the matched text. This is meant first and foremost for list items where the list bullet or numeral ends up in the text. Other use cases may not be well covered.

Parameters
limitBlockDepth

Resets the depth of all the content to at most max.

Parameters
  • max number
  • content ContentState
filterBlockTypes

Converts all block types not present in the list to unstyled. Also sets depth to 0 (for potentially nested list items).

Parameters
  • allowlist readonly string[]
  • content ContentState
filterInlineStyles

Removes all styles not present in the list.

Parameters
  • allowlist readonly string[]
  • content ContentState
cloneEntities

Clones entities in the entityMap, so each range points to its own entity instance. This only clones entities as necessary – if an entity is only referenced in a single range, it won't be changed.

Parameters
  • content ContentState
filterEntityRanges

Filters entity ranges (where entities are applied on text) based on the result of the callback function. Returning true keeps the entity range, false removes it. Draft.js automatically removes entities if they are not applied on any text.

Parameters
  • filterFn function (content: ContentState, entityKey: string, block: BlockNode): boolean
  • content ContentState
shouldKeepEntityType

Keeps all entity types (images, links, documents, embeds) that are enabled.

Parameters
shouldRemoveImageEntity

Removes invalid images – they should only be in atomic blocks. This only removes the image entity, not the camera emoji (📷) that Draft.js inserts.

Parameters
shouldKeepEntityByAttribute

Filters entities based on the data they contain.

Parameters
  • entityTypes readonly {type: string, allowlist: {}?, whitelist: {}?}[]
  • entityType string
  • data { [attr: string]: any }
filterEntityData

Filters data on an entity to only retain what is allowed. This is crucial for IMAGE and LINK, where Draft.js adds a lot of unneeded attributes (width, height, etc).

Parameters
  • entityTypes readonly {type: string, attributes: readonly string>?}[]
  • content ContentState
replaceTextBySpaces

Replaces the given characters by their equivalent length of spaces, in all blocks.

Parameters
  • characters readonly string[]
  • content ContentState
applyContentWithSelection

Applies the new content to the editor state, optionally moving the selection to be on a valid block, inserting one if needed. See #27.

Parameters
  • editorState EditorState
  • content ContentState
  • nextContent ContentState
filterEditorState

Applies filtering and preservation operations to the editor content, to restrict it to supported patterns. Will not alter the editor state if there are no changes to make.

Parameters
  • options FilterOptions
  • editorState EditorState
condenseBlocks

Condenses an array of content blocks into a single block.

  • Skipping the undo-redo stack.
  • Adding a space between each block to match the behavior of vanilla HTML fields.
  • Making sure the space gets the correct styles or entities applied.
  • Placing the selection at the same end offset as the last selection.

This exhibits two known issues:

  • A link / other entity spread over multiple lines will be split into multiple entities of identical data.
  • Upon redo-ing the change, the selection isn’t correctly placed.
Parameters
  • nextState EditorState
  • prevState EditorState

Browser support and polyfills

The Draft.js filters only support modern browsers with ES2020 features. Support for legacy browsers can be achieved, up to IE11, by appropriately transpiling the package’s code and including the required Draft.js polyfills.

Word processor support

Have a look at our test data in pasting/.

Editor - Browser Chrome Windows Chrome macOS Firefox Windows Firefox macOS Edge Windows IE11 Windows Safari macOS Safari iOS Chrome Android
Word 2016 N/A N/A
Word 2010 N/A N/A N/A N/A N/A
Apple Pages N/A N/A N/A N/A N/A
Google Docs
Word Online Unsupported ? ?
Dropbox Paper Unsupported ? ?
Draft.js

Use the Draft.js Cut/Copy/Paste testing plan. We target specific external sources, and have ready-made test documents available to test them:

External sources

Here are external sources we want to pay special attention to, and for which we have ready-made test documents with diverse rich content.

IE11

There are known Draft.js issues with pasting in IE11. For now, we advise users to turn on stripPastedStyles in IE11 only so that Draft.js removes all formatting but preserves whitespace:

const IS_IE11 = !window.ActiveXObject && "ActiveXObject" in window

const editor = <Editor stripPastedStyles={IS_IE11} />

Contributing

See anything you like in here? Anything missing? We welcome all support, whether on bug reports, feature requests, code, design, reviews, tests, documentation, and more. Please have a look at our contribution guidelines.

Credits

View the full list of contributors. MIT licensed. Website content available as CC0.

Microsoft Word toolbars screenshot from PCWorld – Microsoft Word Turns 25 article.