问题
On the following answer to a previous question someone mentioned an "auto-casting bool"
I guess null has an auto-casting bool that is false. What is it, and what does the code that makes it look like?
回答1:
The phrase "auto-casting bool" is a poor phrase someone used off hand. I believe what they mean is the internal ToBoolean operation
Of special note is the if statement which calls ToBoolean on the expression.
I don't know my way around the v8 source code but here is a search for ToBoolean on the v8 repo.
For reference v8 is the javascript implementation used by chrome and written in C++
来源：https://stackoverflow.com/questions/7634584/whats-an-auto-casting-bool