changing indent of selection

gistfile1.txt

import { EditorState, Modifier } from 'draft-js';
import { TAB_CHARACTER } from './CONSTANTS';

const changeIndent = (editorState, isDedent) => {
  const selection = editorState.getSelection();
  const contentState = editorState.getCurrentContent();
  let blockMap = contentState.getBlockMap();
  const blockKeys = blockMap.keySeq();
  const selectionStartKey = selection.getStartKey();
  const selectionEndKey = selection.getEndKey();
  let startKey = selectionStartKey
  let endKey = selectionEndKey

  const startBlock = contentState.getBlockForKey(startKey);
  const endBlock = contentState.getBlockForKey(endKey);
  const blockAfterStart = contentState.getBlockAfter(startKey);
  const blockBeforeEnd = contentState.getBlockBefore(endKey);
  let startOffset = selection.getStartOffset();
  let endOffset = selection.getStartOffset();

  if (startBlock.getText().length <= startOffset && blockAfterStart != null) {
    startKey = blockAfterStart.getKey();
  }

  if (endOffset === 0 && blockBeforeEnd != null) {
    endKey = blockBeforeEnd.getKey();
  }

  const startIndex = blockKeys.indexOf(startKey);
  const endIndex = blockKeys.indexOf(endKey);

  const newContentState = blockMap.takeWhile(block => {
    const blockIndex = blockKeys.indexOf(block.getKey());
    return blockIndex >= startIndex && blockIndex <= endIndex;
  }).reduce((newContentState, block) => {
    const text = block.getText();
    const key = block.getKey();

    let newText = `${TAB_CHARACTER}${text}`

    if (isDedent === true) {
      newText = text.replace(/^\s{1,4}/, '')
    }

    return Modifier.replaceText(
      newContentState,
      selection.merge({
        anchorKey: key,
        focusKey: key,
        anchorOffset: 0,
        focusOffset: 0,
      }),
      newText
    )
  }, contentState);

  const newSelection = selection.merge({
    anchorOffset:
      selection.getAnchorOffset()
      + (
        newContentState.getBlockForKey(selection.getAnchorKey()).getText().length
        - contentState.getBlockForKey(selection.getAnchorKey()).getText().length
      ),
    focusOffset:
      selection.getFocusOffset()
      + (
        newContentState.getBlockForKey(selection.getFocusKey()).getText().length
        - contentState.getBlockForKey(selection.getFocusKey()).getText().length
      ),
  })

  return EditorState.forceSelection(
    EditorState.push(
      editorState,
      newContentState
    ),
    newSelection
  );
}

export {
  changeIndent
}