I saw some code that seems to use an operator I don't recognize, in the form of two exclamation points, like so: !!
. Can someone please tell me what this operator does?
The context in which I saw this was,
this.vertical = vertical !== undefined ? !!vertical : this.vertical;
转载于:https://stackoverflow.com/questions/784929/what-is-the-not-not-operator-in-javascript