AngularJS extend用法詳解及執行個體代碼_AngularJS

AngularJS extend用法

   angular.extend:依次將第二個參數及後續的參數的第一層屬性（不管是簡單屬性還是對象）拷貝賦給第一個參數的第一層屬性，即如果是對象，則是引用的是同一個對象，並返回第一個參數對象。

        執行個體一：var r = angular.extend(b, a);將對象a的第一層屬性（不管是簡單屬性還是對象）拷貝賦給對象b的第一層屬性，即如果是對象，則是引用的是同一個對象，並返回對象b

Js代碼 

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)); 

運行結果：

Text代碼 

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"}} 

         執行個體二：var r = angular.extend(b, a, z);相繼將對象a、z的第一層屬性（不管是簡單屬性還是對象）拷貝賦給對象b的第一層屬性，即如果是對象，則是引用的是同一個對象，並返回對象b

Js代碼 

var a = {   name : 'bijian',   address : 'shenzhen',   family : {     num : 6,     amount : '80W'   } }; var z = {   family : {     amount : '150W',     mainSource : '經營公司'   } }; 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)); 

運行結果：

Text代碼 

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

        再多的執行個體也不如原始碼來的簡單、直接和準確，angular.extend源碼如下：

Js代碼 

/**  * @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; } 

感謝閱讀，希望能協助到大家，謝謝大家對本站的支援！