javascript - Object.assign 覆盖原始引用？

Question

我试图用 Object.assign() “合并”两个对象，但不知何故原始对象被覆盖了。看例子:

var x = {x:1};
var y = {y:2};

var z = Object.assign(x, y);

// what I've expected
console.log(z); // {"x": 1, "y": 2}

// what I haven't expected
console.log(x); // {"x": 1, "y": 2}

Answer 1

对于要创建的新合并对象，必须提供一个空对象作为 Object.assign 的第一个参数。

var x = {
  x: 1
};
var y = {
  y: 2
};

var z = Object.assign({}, x, y);

// new object
console.log(z); // {"x": 1, "y": 2}

// still the same
console.log(x); // {"x": 1}
console.log(y); // {"y": 2}

You can read more information about Object.assign here.