Object.assign vs $ .extend [英] Object.assign vs $.extend

问题描述

鉴于我使用的是不可变对象，我想克隆或复制对象以进行更改。

Given that I am using an immutable object, I want to clone or copy an object in order to make changes.

现在我一直在使用javascript的原生 Object.assign 但偶然发现了JQuery $ .extend 。

Now I have always been using javascript's native Object.assign but stumbled upon the JQuery $.extend.

我想知道更好的方法是什么，两者之间的区别究竟是什么？看看文档，我似乎无法真正找到一个值得注意的差异，为什么选择其中任何一个。

I was wondering what is the better way to do this and what exactly the difference is between both? Looking at the documentation I cannot seem to really find a mentionable difference concerning why to choose either one.

推荐答案

两个主要区别是 deep merge的可选布尔值，它是jQuery $ .extend 方法的递归（其中不支持false ？！）...

The two key differences are the optional boolean for deep merge which is recursive on the jQuery $.extend method (where false is not supported?!) ...

let object1 = {
  id: 1,
  name: {
    forename: 'John',
    surname: 'McClane'
  },
};

let object2 = {
  id: 2,
  name: {
  }
};

// merge objects
let objExtend = $.extend(true, {}, object1, object2);
let objAssign = Object.assign({}, object1, object2);

// diff
console.log(objExtend.name.forename); // "John"
console.log(objAssign.name.forename); //  undefined

Object.assign（）复制属性值。如果源值是对象的引用，则它仅复制该引用值。

Object.assign() copies property values. If the source value is a reference to an object, it only copies that reference value.

示例： JsFiddle

第二个是 $ .extend 方法忽略 undefined ...

The second is the $.extend method ignores undefined ...

let object1 = {
  id: 1,
  name: 'hello world'
};

let object2 = {
  id: 2,
  name: undefined
};

// merge objects
let objExtend = $.extend({}, object1, object2);
let objAssign = Object.assign({}, object1, object2);

// diff
console.log(objExtend.name); // "hello world"
console.log(objAssign.name); //  undefined

示例： JsFiddle

MDN ： Object.assign（target，... sources）

jQuery ： jQuery.extend（[deep]，target，object1 [，objectN]）

如果您正在寻找一种深度合并没有 jQuery的对象的方法，那么这个答案非常好：

If you are looking for a way to deep merge objects without jQuery, this answer is excellent:

如何深度合并而不是浅合并？

E. xample ： JsFiddle

如何使用 Object.assign 与ES6深度合并：

How to deep merge using Object.assign with ES6:

function isObject(item) {
  return (item && typeof item === 'object' && !Array.isArray(item));
}

function mergeDeep(target, ...sources) {
  if (!sources.length) return target;
  const source = sources.shift();

  if (isObject(target) && isObject(source)) {
    for (const key in source) {
      if (isObject(source[key])) {
        if (!target[key]) Object.assign(target, { [key]: {} });
        mergeDeep(target[key], source[key]);
      } else {
        Object.assign(target, { [key]: source[key] });
      }
    }
  }
  return mergeDeep(target, ...sources);
}

这篇关于Object.assign vs $ .extend的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！