如何合并两个对象的对象值

Question

我有两个这样的对象，想合并它们：

const obj1 = {
  1: { foo: 1 },
  2: { bar: 2, fooBar: 3 },
  3: { fooBar: 3 },
};

const obj2 = {
  1: { foo: 1, bar: 2 },
  2: { bar: 2 },
};

const merged = someMergingMethod(obj1, obj2);

merged === {
  1: { foo: 1, bar: 2 },
  2: { bar: 2, fooBar: 3 },
  3: { fooBar: 3 },
};

我的意思是，我不仅要合并对象，还要合并它们的对象值的属性也，如果键是重复的。 因为只是 merged = { ...obj1, ...obj2 }; 用 obj2 覆盖了属性。

最简单的方法是什么？

我可以使用 ES2017 和 lodash 等其他库。

Answer 1

您可以使用扩展运算符。

更新：

如果 obj2 有一些 obj1 没有的属性？

最初我写了这个答案，假设键的索引像0,1 and so on，但正如你在评论中提到的那样，情况并非如此，你可以构建一个键数组，而不是像这样迭代它

@Nick [...Object.keys(obj1), ...Object.keys(obj2)] 在评论中非常简洁地添加了

let obj1 = {1: { foo: 1 },2: { bar: 2, fooBar: 3 },3: { fooBar: 3 },};
let obj2 = {1: { foo: 1, bar: 2 },2: { bar: 2 },};

let keys = [...new Set([...Object.keys(obj1),...Object.keys(obj2)])]
let  op = {}
let merged = keys.forEach(key=>{
  op[key] = {
    ...obj1[key],
    ...obj2[key]
  }
})
console.log(op)

Answer 2

既然你提到你可以使用 lodash 你可以像这样使用merge：

_.merge(obj1, obj2)

得到你想要的结果。

请参阅下面的工作示例：

const a = {
  1: { foo: 1 },
  2: { bar: 2, fooBar: 3 },
  3: { fooBar: 3 },
},

b = {
  1: { foo: 1, bar: 2 },
  2: { bar: 2 },
  4: {foo: 1}
},

res = _.merge(a, b);
console.log(res);

<script src="https://cdn.jsdelivr.net/lodash/4.16.4/lodash.min.js"></script>

Answer 3

我有你想要的。 此函数将遍历每个嵌套对象并将其与其他对象组合。我只用树下的 5 个嵌套级别对其进行了测试，但理论上，它应该适用于任意数量的嵌套对象，因为它是一个递归函数。

//this function is similar to object.assign but,
//leaves the keys which are common among both bojects untouched
function merge(object1, object2)
{
    function combine(p, q)
    {
        for(i in q)
            if(!p.hasOwnProperty(i))
                p[i]= q[i];
        return p;
    }
    obj1= Object.assign(combine(obj1, obj2), obj1);//for the first level 
    obj1= Object.assign(traverse(obj1, obj2), obj1);//for subsequent levels down theobjectt tree

//this function traverses each nested boject and combines it with the other object
    function traverse(a, b)
    {
        if(typeof(a) === "object" && typeof(b) === "object")
            for(i in b)
                if(typeof(a[i]) === "object" && typeof(b[i]) === "object")
                    a[i]= Object.assign(traverse(a[i], b[i]), a[i]);
                else
                    Object.assign(combine(a, b), a);
        return a;
    }
    return obj1;
}

console.log(merge(obj1, obj2));

这是一个更复杂的对象合并的工作示例

var obj1 = {
  1: { foo: 1 },
  2: { bar: 2, fooBar: 3 },
  3: { fooBar: 3, boor:{foob: 1, foof: 8} },
  4: {continent: {
  		asia: {country: {india: {capital: "delhi"}, china: {capital: "beiging"}}},
  		europe:{country:{germany: {capital: "berlin"},france: {capital: "paris"}}}
  	},
  	vegtables: {cucumber: 2, carrot: 3, radish: 7}
  }
};

var obj2 = {
  1: { foo: 1, bar: 2 },
  2: { bar: 2 },
  3: {fooBar: 3, boor:{foob: 1, boof: 6}, boob: 9 },
  4: {continent: {
  		northamerica: {country: {mexico: {capital: "mexico city"}, canada: {capital: "ottawa"}},},
  		asia: {country: {Afghanistan : {capital: "Kabul"}}}
  	}
  },
  5: {barf: 42}
};

//this function is similar to object.assign but,
//leaves the keys which are common among both bojects untouched
function merge(object1, object2)
{
	function combine(p, q)
	{
		for(i in q)
			if(!p.hasOwnProperty(i))
				p[i]= q[i];
		return p;
	}
	obj1= Object.assign(combine(obj1, obj2), obj1);//for the first level 
	obj1= Object.assign(traverse(obj1, obj2), obj1);//for subsequent levels down the object tree

//this function traverses each nested boject and combines it with the other object
	function traverse(a, b)
	{
		if(typeof(a) === "object" && typeof(b) === "object")
			for(i in b)
				if(typeof(a[i]) === "object" && typeof(b[i]) === "object")
					a[i]= Object.assign(traverse(a[i], b[i]), a[i]);
				else
			 		Object.assign(combine(a, b), a);
		return a;
	}
	return obj1;
}

console.log(merge(obj1, obj2));

Answer 4

您可以使用 Object.assign 并将对象属性分配给空对象。

var a =  {books: 2};
var b = {notebooks: 1};
var c = Object.assign( {}, a, b );
console.log(c);

或

您可以使用 Lodash 库中的合并方法。 可以在这里查看： https://www.npmjs.com/package/lodash

Answer 5

你是这样的吗？

我们可以用这种方式合并两个对象。

const person = { name: 'David Walsh', gender: 'Male' };
const attributes = { handsomeness: 'Extreme', hair: 'Brown', eyes: 'Blue' };
const summary = {...person, ...attributes};

/*

Object {
  "eyes": "Blue",
  "gender": "Male",
  "hair": "Brown",
  "handsomeness": "Extreme",
  "name": "David Walsh",
}

*/