regular-redux-undo/src/util/index.js

the plugin of regular-redux to archieve undo and redo

/**
 * 类型判断
 * @param {item} target 检测对象
 */

export function typeOf(target) {
  return Object.prototype.toString.call(target).slice(8, -1).toLowerCase();
}

/**
 * shallowly copy of an object or an array
 * @param {Object or array} target 
 * @return {Object or array} the new one
 */
export function clone(target) {
  let type = typeOf(target);

  if (type === 'array') {
    return [].slice.call(target);
  }
  if (type === 'object') {
    return Object.assign({}, target);
  }
  return target;
}

/**
 * to extend an object, when the parameter(overwrite) is true , It equals to Object.assign
 * @param {Object} to the target object
 * @param {Object} from the reference object
 * @param {Boolean} overwrite force to overwrite the value whether the old value is existed or not
 * @return the target object after extended
 */
export function extend(to, from, overwrite) {
  if (typeOf(to) !== 'object' || typeOf(from) !== 'object') {
    return to;
  }
  for (let i in from) {
    if (overwrite || to[i] === undefined || to[i] == null) {
      to[i] = from[i];
    }
  }
  return to;
}

/**
 * to see an object or an array is empty or not
 * @param {Object or Array} target 
 * @return {Boolean} the result
 */
export function isEmpty(target) {
  
  let type = typeOf(target);

  if (type === 'object') {
    return !Object.keys(target).length;
  }
  if (type === 'array') {
    return !target.length;
  }
  return true;
}

/**
 * the forEach of an object
 * @param {Object} obj the target to traverse
 * @param {*} fn 
 */
export function forEachValue(obj = {}, fn) {
  Object.keys(obj).forEach(key => fn(obj[key], key))
}

/**
 * determine whether a condition is true or not
 * @param {Boolean Expression} condition the expression to be judged
 * @param {String} msg the message to throw when the condition is false
 */
export function assert(condition, msg) {
  if (!condition) throw new Error(`[regular-redux] ${msg}`)
}

/**
 * log a warning by some condition
 * @param {Boolean Expression} condition the expression to be judged
 * @param {String} msg the message to throw when the condition is true
 */
export function warning(condition, msg) {
  if (condition) console.warn(`[regular-redux] ${msg}`)
}

/**
 * log a error by some condition
 * @param {Boolean Expression} condition the expression to be judged
 * @param {String} msg the message to throw when the condition is true
 */
export function error(condition, msg) {
  if (condition) console.error(`[regular-redux] ${msg}`)
}