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);