我需要能够在运行时合并两个(非常简单的)JavaScript 对象。例如,我想:
var obj1 = { food: 'pizza', car: 'ford' }
var obj2 = { animal: 'dog' }
obj1.merge(obj2);
//obj1 now has three properties: food, car, and animal
有没有人有这个脚本或知道内置的方式来做到这一点?我不需要递归,我不需要合并函数,只需要平面对象上的方法。
ECMAScript 2018 标准方法
你会使用对象传播 :
let merged = {...obj1, ...obj2};
/** There's no limit to the number of objects you can merge.
* Later properties overwrite earlier properties with the same name. */
const allRules = {...obj1, ...obj2, ...obj3};
ECMAScript 2015(ES6)标准方法
/* For the case in question, you would do: */
Object.assign(obj1, obj2);
/** There's no limit to the number of objects you can merge.
* All objects get merged into the first object.
* Only the object in the first argument is mutated and returned.
* Later properties overwrite earlier properties with the same name. */
const allRules = Object.assign({}, obj1, obj2, obj3, etc);
(参见MDN JavaScript 参考 )
ES5 和早期的方法
for (var attrname in obj2) { obj1[attrname] = obj2[attrname]; }
请注意,这只会将obj2
所有属性添加到obj1
,如果您仍想使用未修改的obj1
,则可能不是您想要的。
如果你正在使用一个遍布原型的框架,那么你必须使用像hasOwnProperty
这样的检查来获得更好的功能,但是该代码适用于 99%的情况。
功能示例:
/**
* Overwrites obj1's values with obj2's and adds obj2's if non existent in obj1
* @param obj1
* @param obj2
* @returns obj3 a new object based on obj1 and obj2
*/
function merge_options(obj1,obj2){
var obj3 = {};
for (var attrname in obj1) { obj3[attrname] = obj1[attrname]; }
for (var attrname in obj2) { obj3[attrname] = obj2[attrname]; }
return obj3;
}
jQuery 还有一个实用工具: http : //api.jquery.com/jQuery.extend/ 。
取自 jQuery 文档:
// Merge options object into settings object
var settings = { validate: false, limit: 5, name: "foo" };
var options = { validate: true, name: "bar" };
jQuery.extend(settings, options);
// Now the content of settings object is the following:
// { validate: true, limit: 5, name: "bar" }
上面的代码将改变现有的名为settings
对象 。
如果要在不修改任何参数的情况下创建新对象 ,请使用以下命令:
var defaults = { validate: false, limit: 5, name: "foo" };
var options = { validate: true, name: "bar" };
/* Merge defaults and options, without modifying defaults */
var settings = $.extend({}, defaults, options);
// The content of settings variable is now the following:
// {validate: true, limit: 5, name: "bar"}
// The 'defaults' and 'options' variables remained the same.
Harmony ECMAScript 2015(ES6)指定了Object.assign
,它将执行此操作。
Object.assign(obj1, obj2);