AngularJS extend用法详解及实例代码-PHP开发-php.cn

AngularJS extend用法详解及实例代码

高洛峰

Lepaskan： 2016-12-06 16:24:31

asal

1492 orang telah melayarinya

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 : &#39;bijian&#39;,
  address : &#39;shenzhen&#39;,
  family : {
    num : 6,
    amount : &#39;80W&#39;
  }
};
var b = {};
var r = angular.extend(b, a);
console.log(&#39;a:&#39; + JSON.stringify(a));
console.log(&#39;b:&#39; + JSON.stringify(b));
console.log(&#39;r:&#39; + JSON.stringify(r));
  
b.address = &#39;hanzhou&#39;;
b.family.amount = &#39;180W&#39;;
console.log(&#39;a:&#39; + JSON.stringify(a));
console.log(&#39;b:&#39; + JSON.stringify(b));
console.log(&#39;r:&#39; + JSON.stringify(r));

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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"}}

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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 : &#39;bijian&#39;,
  address : &#39;shenzhen&#39;,
  family : {
    num : 6,
    amount : &#39;80W&#39;
  }
};
var z = {
  family : {
    amount : &#39;150W&#39;,
    mainSource : &#39;经营公司&#39;
  }
};
var b = {};
var r = angular.extend(b, a, z);
console.log(&#39;a:&#39; + JSON.stringify(a));
console.log(&#39;b:&#39; + JSON.stringify(b));
console.log(&#39;r:&#39; + JSON.stringify(r));
  
b.address = &#39;hanzhou&#39;;
b.family.amount = &#39;180W&#39;;
console.log(&#39;a:&#39; + JSON.stringify(a));
console.log(&#39;b:&#39; + JSON.stringify(b));
console.log(&#39;r:&#39; + JSON.stringify(r));

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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"}}

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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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