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

问题描述

我尝试克隆具有嵌套对象的对象数组.

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 _.clone 方法和 isDeep<true 处的/code> 参数:

_.Clone

With the _.clone method and the isDeep parameter at true:

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

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

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

我期望 clone[1].values.d == 'd' :

如果 isDeep 为真，嵌套对象也将被克隆，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.

怎么了?

此外，当我尝试使用 _.cloneDeep 方法时，我收到一个错误:

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'

为什么会出现这个错误?

Why this error?

使用 $.extend 克隆没有引用原始对象如预期:

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.

因为我也使用 Backbone.js，所以我加载了一个与 Backbone 和 Underscore 兼容的 Lodash 的特殊版本，它禁用了一些功能.在这个例子中:

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';

• 普通构建:_.isEqual(data, clone) === false
• 使用 Underscore 构建:_.isEqual(data, clone) === true

我刚刚在我的 Backbone 应用程序中用普通版本替换了 Underscore 版本，该应用程序仍在工作.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.

Edit 2018: Underscore 构建 似乎不再存在.如果您在 2018 年阅读本文，您可能会对本文档感兴趣(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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