破坏性地映射对象属性函数 [英] Destructively map object properties function

问题描述

我正在寻找一个示例或解决方案，用于破坏性地映射或更改对象的值，而不是返回新对象或旧对象的副本。可以使用underscore.js，因为项目已经使用这个第三方库。

I was looking for an example or solution for mapping or changing values of an object 'destructively' instead of returning a new object or copy of the old object. underscore.js can be used since the project already uses this third party library.

推荐答案

这就是这样一个解决方案的样子，使用下划线：

This is how one such solution could look like, using underscore:

function mapValuesDestructive (object, f) {
  _.each(object, function(value, key) {
    object[key] = f(value);
  });
}

示例映射函数：

an example mapper function:

function simpleAdder (value) {
  return value + 1;
}

以及示例用法如下：

and example usage as follows:

var counts = {'first' : 1, 'second' : 2, 'third' : 3};
console.log('counts before: ', counts);
// counts before:  Object {first: 1, second: 2, third: 3}

mapValuesDestructive(counts, simpleAdder);
console.log('counts after: ', counts);
//counts after:  Object {first: 2, second: 3, third: 4}

工作演示： http://jsbin.com/yubahovogi/edit?js,output

（不要忘记打开您的控制台/ devtools;>）

(don't forget to open your console / devtools ;> )

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