什么是＆QUOT;自动浇注布尔＆QUOT;？ [英] What's an "auto-casting bool"?

问题描述

在以下<一个href=\"http://stackoverflow.com/questions/7634343/null-is-type-object-so-its-truthy-whats-going-on-behind-the-scenes/7634374#7634374\">answer到有人提到自动铸造BOOL一previous问题

On the following answer to a previous question someone mentioned an "auto-casting bool"

我猜空具有自动铸造布尔那是假的。这是什么，又是什么在code，使得它看起来像？

I guess null has an auto-casting bool that is false. What is it, and what does the code that makes it look like?

推荐答案

短语自动铸造BOOL是一个贫穷的短语有人用了手。我相信，他们的意思是内部 ToBoolean 操作

The phrase "auto-casting bool" is a poor phrase someone used off hand. I believe what they mean is the internal ToBoolean operation

特别值得注意的是， if语句这就要求 ToBoolean 的前pression。

Of special note is the if statement which calls ToBoolean on the expression.

我不知道我周围的V8源$ C ​​$ C的方式，但这里是一个<一个href=\"http://www.google.com/$c$csearch#search&q=toboolean+package%3ahttp://v8%5C.google$c$c%5C.com\"相对=nofollow>搜索 ToBoolean 的V8回购。

I don't know my way around the v8 source code but here is a search for ToBoolean on the v8 repo.

有关参考V8是用铬和C ++编写的JavaScript执行

For reference v8 is the javascript implementation used by chrome and written in C++

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