angular forEach方法遍历源码解读

angular中提供了forEach()方法用于遍历对象或数组，供大家参考，具体内容如下

function forEach(obj, iterator, context) { var key, length; if (obj) { if (isFunction(obj)) { for (key in obj) { // Need to check if hasOwnProperty exists, // as on IE8 the result of querySelectorAll is an object without a hasOwnProperty function if (key != 'prototype' && key != 'length' && key != 'name' && (!obj.hasOwnProperty || obj.hasOwnProperty(key))) { iterator.call(context, obj[key], key, obj); } } } else if (isArray(obj) || isArrayLike(obj)) { var isPrimitive = typeof obj !== 'object'; for (key = 0, length = obj.length; key < length; key++) { if (isPrimitive || key in obj) { iterator.call(context, obj[key], key, obj); } } } else if (obj.forEach && obj.forEach !== forEach) { obj.forEach(iterator, context, obj); } else if (isBlankObject(obj)) { // createMap() fast path --- Safe to avoid hasOwnProperty check because prototype chain is empty for (key in obj) { iterator.call(context, obj[key], key, obj); } } else if (typeof obj.hasOwnProperty === 'function') { // Slow path for objects inheriting Object.prototype, hasOwnProperty check needed for (key in obj) { if (obj.hasOwnProperty(key)) { iterator.call(context, obj[key], key, obj); } } } else { // Slow path for objects which do not have a method `hasOwnProperty` for (key in obj) { if (hasOwnProperty.call(obj, key)) { iterator.call(context, obj[key], key, obj); } } } } return obj; }

官方描述：

forEach方法可以遍历数组或对象，函数有三个参数为别为：value，key,obj。
1）、value value指当遍历的对象或数组元素当前的值
2)、 key 是对象属性的的key或者数组的索引
3)、 obj obj即被遍历的对象或数组本身

示例：

var values = {name: 'misko', gender: 'male'}; var log = []; angular.forEach(values, function(value, key) { this.push(key + ': ' + value); }, log);