@mirrormedia/lilith-draft-editor/lib/draft-js/modifier.js

## Installation

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.Modifier = void 0;

var _draftJs = require("draft-js");

var _immutable = require("immutable");

/* 
    This method is specified for custom inline style such as 'FONT_COLOR_#ffffff'.
    For this kind of inline style there may be more than one style name 'FONT_COLOR_#ffffff', 'FONT_COLOR_#000000'.
    To prevent any nested specific inline style got rendered after the outer inline style being removed, 
    clear all specific inline styles when custom inline style is applied or removed.

    Since getCurrentInlineStyle only return the inline style the starting position contains,
    loop through all char of blocks to remove all nested inline styles.

    Reference: https://github.com/facebook/draft-js/blob/main/src/model/transaction/ContentStateInlineStyle.js#L39-L88
  */
const removeInlineStyleByPrefix = (contentState, selectionState, inlineStylePrefix) => {
  const blockMap = contentState.getBlockMap();
  const startKey = selectionState.getStartKey();
  const startOffset = selectionState.getStartOffset();
  const endKey = selectionState.getEndKey();
  const endOffset = selectionState.getEndOffset(); // loop through all selected blocks and every block chars to remove specific inline style

  const newBlocks = blockMap.skipUntil((_, k) => k === startKey).takeUntil((_, k) => k === endKey).concat((0, _immutable.Map)([[endKey, blockMap.get(endKey)]])).map((block, blockKey) => {
    let sliceStart;
    let sliceEnd;

    if (startKey === endKey) {
      sliceStart = startOffset;
      sliceEnd = endOffset;
    } else {
      sliceStart = blockKey === startKey ? startOffset : 0;
      sliceEnd = blockKey === endKey ? endOffset : block.getLength();
    }

    let chars = block.getCharacterList();
    let current;

    while (sliceStart < sliceEnd) {
      current = chars.get(sliceStart);
      const inlineStyle = current.getStyle().find(styleName => styleName.startsWith(inlineStylePrefix));

      if (inlineStyle) {
        chars = chars.set(sliceStart, _draftJs.CharacterMetadata.removeStyle(current, inlineStyle));
      }

      sliceStart++;
    }

    return block.set('characterList', chars);
  });
  return contentState.merge({
    blockMap: blockMap.merge(newBlocks),
    selectionBefore: selectionState,
    selectionAfter: selectionState
  });
};

const Modifier = Object.assign({}, _draftJs.Modifier, {
  removeInlineStyleByPrefix
});
exports.Modifier = Modifier;