AngularJS extend用法详解及实例代码

AngularJS extend用法
angular.extend:依次将第二个参数及后续的参数的第一层属性（不管是简单属性还是对象）拷贝赋给第一个参数的第一层属性，即如果是对象，则是引用的是同一个对象，并返回第一个参数对象。

实例一：var r = angular.extend（b, a）;将对象a的第一层属性（不管是简单属性还是对象）拷贝赋给对象b的第一层属性，即如果是对象，则是引用的是同一个对象，并返回对象b

Js代码

var a = { name : "bijian", address : "shenzhen", family : { num : 6, amount : "80W" } }; var b = {}; var r = angular.extend（b, a）; console.log（"a:" + JSON.stringify（a））; console.log（"b:" + JSON.stringify（b））; console.log（"r:" + JSON.stringify（r））;b.address = "hanzhou"; b.family.amount = "180W"; console.log（"a:" + JSON.stringify（a））; console.log（"b:" + JSON.stringify（b））; console.log（"r:" + JSON.stringify（r））;

运行结果：

Text代码

a:{"name":"bijian","address":"shenzhen","family":{"num":6,"amount":"80W"}} b:{"name":"bijian","address":"shenzhen","family":{"num":6,"amount":"80W"}} r:{"name":"bijian","address":"shenzhen","family":{"num":6,"amount":"80W"}} a:{"name":"bijian","address":"shenzhen","family":{"num":6,"amount":"180W"}} b:{"name":"bijian","address":"hanzhou","family":{"num":6,"amount":"180W"}} r:{"name":"bijian","address":"hanzhou","family":{"num":6,"amount":"180W"}}

实例二：var r = angular.extend（b, a, z）;相继将对象a、z的第一层属性（不管是简单属性还是对象）拷贝赋给对象b的第一层属性，即如果是对象，则是引用的是同一个对象，并返回对象b

Js代码

var a = { name : "bijian", address : "shenzhen", family : { num : 6, amount : "80W" } }; var z = { family : { amount : "150W", mainSource : "经营公司" } }; var b = {}; var r = angular.extend（b, a, z）; console.log（"a:" + JSON.stringify（a））; console.log（"b:" + JSON.stringify（b））; console.log（"r:" + JSON.stringify（r））;b.address = "hanzhou"; b.family.amount = "180W"; console.log（"a:" + JSON.stringify（a））; console.log（"b:" + JSON.stringify（b））; console.log（"r:" + JSON.stringify（r））;

运行结果：

Text代码

a:{"name":"bijian","address":"shenzhen","family":{"num":6,"amount":"80W"}} b:{"name":"bijian","address":"shenzhen","family":{"amount":"150W","mainSource":"经营公司"}} r:{"name":"bijian","address":"shenzhen","family":{"amount":"150W","mainSource":"经营公司"}} a:{"name":"bijian","address":"shenzhen","family":{"num":6,"amount":"80W"}} b:{"name":"bijian","address":"hanzhou","family":{"amount":"180W","mainSource":"经营公司"}} r:{"name":"bijian","address":"hanzhou","family":{"amount":"180W","mainSource":"经营公司"}}

再多的实例也不如源代码来的简单、直接和准确，angular.extend源码如下：

Js代码

/*** @ngdoc function* @name angular.extend* @function** @description* Extends the destination object `dst` by copying all of the properties from the `src` object（s）* to `dst`. You can specify multiple `src` objects.** @param {Object} dst Destination object.* @param {...Object} src Source object（s）.* @returns {Object} Reference to `dst`.*/ function extend（dst） {var h = dst.$$hashKey;forEach（arguments, function（obj）{ if （obj ！== dst） {forEach（obj, function（value, key）{ dst[key] = value;}）; }}）; setHashKey（dst,h）;return dst; }

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