question/implement-immutability-helper

[giscus[bot]]

question/implement-immutability-helper

北美前端面试攻略

https://us-fe.github.io/question/implement-immutability-helper.html

[xiaoyu2er]

参考高赞答案

/**
 * @param {any} data
 * @param {Object} command
 */
function update(data, command) {
  for (const [key, val] of Object.entries(command)) {
    switch (key) {
      case '$push':
        return [...data, ...val];
      case '$set':
        return val;
      case '$merge':
        if (typeof data !== 'object' || data === null) {
          throw new Error('data should be an object');
        }
        return {
          ...data,
          ...val,
        }
      case '$apply':
        return val(data);
      default:
        const newData = Array.isArray(data) ? [...data] : { ...data };
        newData[key] = update(newData[key], val);
        return newData;
    }
  }
}