updateLocks.js

const hasFocus = editorState.getSelection().getHasFocus();
if (hasFocus) {
  // make an array of blocks we need to request locks for
  // 1. which locks do we currently have?
  const currentLocks = this.locks.map(lock => lock.blockKey);
  // 2. which locks does the user want? (getSelectedBlocks)
  const desiredLocks = getSelectedBlocks().map(block => block.getKey());
  // 3. Make a list of all elements in the desiredLocks not contained in currentLocks
  const requestLocks = R.difference(desiredLocks, currentLocks);
  // 4. Make a list of all elements in currentLocks not contained in desiredLocks
  const releaseLocks = R.difference(currentLocks, desiredLocks);
  // 5. send the request for those
  requestBlockLocks(requestLocks, user);
  releaseBlockLocks(releaseLocks, user);
} else {
  releaseAllBlockLocks(user);
}