Shorthand for flipping a boolean variable

问题

How can I flip the value of a boolean variable in javascript, without having to include the variable name twice? So

foobarthings[foothing][barthing] = !foobarthings[foothing][barthing];

without writing foobarthings[foothing][barthing] twice.

回答1:

There is no shorter way than what you currently have.

回答2:

You can do this:

foo ^= 1

But this really switches foo between 0 and 1, not true and false.

回答3:

var value = true;
alert(value);
value ^= true;
alert(value);​

You could get 1 or 0 here

回答4:

To flip the value of a boolean variable in JS you need the syntax like this:

return !foo;

It's really that easy...

Or you can do (foo ^= 1) == true (must be == not ===)

回答5:

You can have just foo and !foo in the place where you execute it or check the condition.

来源：https://stackoverflow.com/questions/13972887/shorthand-for-flipping-a-boolean-variable