javascript属性值依赖于其他属性 | javascript属性值依赖于其他属性

本文介绍了javascript属性值依赖于其他属性的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我创建了一个名为Fullscreen的对象，并在对象内另一个名为directions的对象。所以我的代码如下所示：

I made an object called Fullscreen, and within the object another object called directions. so my code looks like this:

FullScreen = {
  directions: {
    prev: -1,
    next: 1
  }
}

但我想要能够从对象外部设置FullScreen.directions.prev，并将FullScreen.directions.next更改为prev的负值。任何想法如何做到这一点？

but i want to be able to set FullScreen.directions.prev from outside the object, and change FullScreen.directions.next to the negative value of the prev. any ideas how to do this?

推荐答案

如果我正确理解了这个问题，就像这样简单：

If I understand the question correctly, it's as simple as this:

FullScreen.directions.prev = -42;
FullScreen.directions.next = -FullScreen.directions.prev;

然而，将此逻辑封装在函数中可能会更好：

It might be better, however, to encapsulate this logic in a function:

FullScreen = {
  directions: {
    prev: -1,
    next: 1,
    setPrev: function (value) {
        value = +value; // coerce to number
        this.prev = value;
        this.next = -value;
    }
  }
}

// then
FullScreen.direction.setPrev(-42);

您可以使用：

You could get even fancier using the special get/set syntax:

FullScreen = {
  directions: {
    _prev: -1,
    _next: 1,
    get prev() {
        return this._prev;
    },
    set prev(value) {
        value = +value; // coerce to number
        this._prev = value;
        this._next = -value;
    },
    get next() {
        return this._next;
    }
  }
}

// then
FullScreen.direction.prev = -42;
// invokes the setter function behind the scenes, so that _next is also set

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