darkness-dependent-vision/src/hooks/updateToken.js

// SPDX-FileCopyrightText: 2021 Johannes Loher
//
// SPDX-License-Identifier: MIT

export default function registerForUpdateTokenHook() {
  Hooks.on('updateToken', onUpdateToken);
}

function onUpdateToken(token, change) {
  const shouldUpdateVisionSource = [
    'dimVisionDarknessMin',
    'dimVisionDarknessMax',
    'brightVisionDarknessMin',
    'brightVisionDarknessMax',
  ].some((flagKey) => `flags.darkness-dependent-vision.${flagKey}` in foundry.utils.flattenObject(change));
  if (shouldUpdateVisionSource) {
    token.object.updateVisionSource();
  }
}