我需要能够在运行时合并两个(非常简单)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

是否有一种内置的方法来实现这一点?我不需要递归,也不需要合并函数,只需要平面对象上的方法。


当前回答

原型中的正确实现应该如下所示:

var obj1 = {food: 'pizza', car: 'ford'}
var obj2 = {animal: 'dog'}

obj1 = Object.extend(obj1, obj2);

其他回答

有三种方法可以做到这一点:-

方法1:-

// using spread ...
    let obj1 = {
        ...obj2
    };

方法2:-

// using  Object.assign() method
let obj1 = Object.assign({}, obj2);

方法3:-

// using JSON
let obj1 = JSON.parse(JSON.stringify(obj2));

对于不太复杂的对象,可以使用JSON:

var obj1 = { food: 'pizza', car: 'ford' }
var obj2 = { animal: 'dog', car: 'chevy'}
var objMerge;

objMerge = JSON.stringify(obj1) + JSON.stringify(obj2);

// {"food": "pizza","car":"ford"}{"animal":"dog","car":"chevy"}

objMerge = objMerge.replace(/\}\{/, ","); //  \_ replace with comma for valid JSON

objMerge = JSON.parse(objMerge); // { food: 'pizza', animal: 'dog', car: 'chevy'}
// Of same keys in both objects, the last object's value is retained_/

请注意,在此示例中,“}{”不能出现在字符串中!

对于使用Node.js的用户,有一个NPM模块:Node.extend

安装:

npm install node.extend

用法:

var extend = require('node.extend');
var destObject = extend(true, {}, sourceObject);
// Where sourceObject is the object whose properties will be copied into another.

您可以为每个对象分配一个默认的合并(也许“继承”一个更好的名称)方法:

它应该使用对象或实例化函数。

如果需要,下面的代码处理重写合并值:

Object.prototype.merge = function(obj, override) {
// Don't override by default

    for (var key in obj) {
        var n = obj[key];
        var t = this[key];
        this[key] = (override && t) ? n : t;
    };

};

测试数据如下:

var Mammal = function () {
    this.eyes = 2;
    this.thinking_brain = false;
    this.say = function () {
    console.log('screaming like a mammal')};
}

var Human = function () {
    this.thinking_brain = true;
    this.say = function() {console.log('shouting like a human')};
}

john = new Human();

// Extend mammal, but do not override from mammal
john.merge(new Mammal());
john.say();

// Extend mammal and override from mammal
john.merge(new Mammal(), true);
john.say();

我的方式:

function mergeObjects(defaults, settings) {
    Object.keys(defaults).forEach(function(key_default) {
        if (typeof settings[key_default] == "undefined") {
            settings[key_default] = defaults[key_default];
        } else if (isObject(defaults[key_default]) && isObject(settings[key_default])) {
            mergeObjects(defaults[key_default], settings[key_default]);
        }
    });

    function isObject(object) {
        return Object.prototype.toString.call(object) === '[object Object]';
    }

    return settings;
}

:)