javascript - 如何防止 javascript 在传递对象的子对象时通过引用传递

Question

在我的项目中有一个单色屏幕，您可以写入和清除。在类里面，我有这两行代码用于清除屏幕。第一个将当前像素值从屏幕推送到堆栈上，以便稍后可以撤消清屏。第二行清除屏幕。问题是撤消堆栈正在获取对 this.pixels 的引用，而不是获取它当时的值。

this.pushUndo(this.pixels); //this.pixels is an array of ints
this.updateScreen(new Array(64*32)); //this.pixels changes at the end of this line but the undo stack shouldn't change its value

Answer 1

您可以使用slice创建浅副本:

const pixels0 = [0, 1, 2, 3, 4, 5];
const pixels1 = pixels0.slice(0);

// modify only index 0 of copy.
pixels1[0] = 1;

console.log(pixels0);
// expected output: Array [0, 1, 2, 3, 4, 5]

console.log(pixels1);
// expected output: Array [1, 1, 2, 3, 4, 5]

如果您需要深层副本，可以查看What is the most efficient way to deep clone an object in JavaScript?