Lodash .clone和.cloneDeep行为 [英] Lodash .clone and .cloneDeep behaviors

问题描述

我尝试使用嵌套对象克隆一个对象数组。

I try to clone an array of objects with nested objects.

类似于：

var data = [
    { id: 1, values: { a: 'a', b: 'b' } },
    { id: 2, values: { c: 'c', d: 'd' } }
];

_。克隆

使用< a href =http://lodash.com/docs#clone =noreferrer> _。clone 方法和 isDeep 参数 true ：

var clone = _.clone(data, true);

data[1].values.d = 'x';

console.log( _.isEqual(data, clone) ); // true, clone[1].values.d == 'x'

我预计 clone [1] .values.d =='d'：

如果isDeep是也将克隆真正的嵌套对象，否则它们将通过引用分配
。

If isDeep is true nested objects will also be cloned, otherwise they will be assigned by reference.

有什么问题？

此外，当我尝试 _.cloneDeep 方法，我收到错误：

In addition, when I try with the _.cloneDeep method, I get an error:

var clone = _.cloneDeep(data);

// Uncaught TypeError: Object function u(n){return n instanceof u?n:new o(n)}
// has no method 'cloneDeep'

为什么会出现此错误？

使用 $ .extend 克隆没有按预期引用原始对象：

With $.extend the clone has no reference to the original object as expected:

var clone = $.extend(true, {}, data);

console.log( _.isEqual(data, clone) ); // false, clone[1].values.d == 'd' 

推荐答案

感谢Gruff Bunny和Louis的评论，我找到了问题的根源。

Thanks to Gruff Bunny and Louis' comments, I found the source of the issue.

当我使用Backbone.js时，我加载了一个特殊的与Backbone和Underscore兼容的Lodash版本可以禁用某些功能。在此示例中：

As I use Backbone.js too, I loaded a special build of Lodash compatible with Backbone and Underscore that disables some features. In this example:

var clone = _.clone(data, true);

data[1].values.d = 'x';

• 正常构建： _。isEqual（data，clone）=== false


• 使用Underscore版本 ： _。isEqual（data，clone）== = true


• with the Normal build: _.isEqual(data, clone) === false
• with the Underscore build: _.isEqual(data, clone) === true

我刚用Backbone应用程序中的Normal build替换了Underscore版本，应用程序是还在工作。所以我现在可以使用具有预期行为的Lodash .clone。

I just replaced the Underscore build with the Normal build in my Backbone application and the application is still working. So I can now use the Lodash .clone with the expected behaviour.

编辑2018： Underscore构建似乎不再存在。如果您在2018年阅读本文，可能会对此文档感兴趣（Backbone和Lodash ）。

Edit 2018: the Underscore build doesn't seem to exist anymore. If you are reading this in 2018, you could be interested by this documentation (Backbone and Lodash).

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