JavaScript Void Keyword

February 14, 2018

2 min read

The void keyword is an operator that evalutes the expression following it as undefined every time. The most common usage of this keyword seems to be as a way to access the JavaScript primitive value undefined as void(0) (it could be any expression, but (0) is convention). In most current development environments it would be equivalent to use undefined instead. This seems like it would only come up when targeting older browsers, which is why void(0) can be found in Babel transpiled code.

#examples

void true; // undefined
void false; // undefined
void 0; // undefined

#sources

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/void https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined