_（variable_name）在javascript中的含义是什么？

问题描述

我遇到了以下javascript代码：

I came across the following javascript code:

this.removeEdge = function(source, target) {
  if(!_states[source]) return;

  var children = _states[source].children,
      index = _(children).indexOf(target);
  if(index !== -1) children.splice(index, 1);
};

_（儿童）是什么意思？

What does _(children) mean?

推荐答案

_ 是JavaScript中的有效变量标识符，理论上可以引用任何。使用带函数语法的 _（...）意味着 _ 是一个函数。

_ is a valid variable identifier in JavaScript, and could theoretically refer to anything. Using _(...) with function syntax implies that _ is a function.

也就是说，它通常由库使用，但如果您正在查看缩小的代码，它很可能被用作另一个单字符变量名来保存文件大小。

That said, it is commonly used by the underscore.js library, however if you're looking at minified code, it's quite possibly being used as another single-character variable name to save on file size.

在你提供的例子中，似乎underscore.js用于将 children 作为集合处理，以便可以应用于集合。这与调用类似：

In your example provided, it appears that underscore.js is being used to treat children as a collection, so that the indexOf function can be applied to the collection. This would be similar to calling:

_.indexOf(children, target);

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