Why Does Void In Javascript Require An Argument?

From what I understand, the keyword void in Javascript is some kind of function that takes one argument and always returns the undefined value. For some reason you need to pass it

Solution 1:

As per this page https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/void void is an operator, which simply returns undefined, after evaluating the expression you pass to it. An operator needs an operand to operate on. That is why pass a parameter.

console.log(voidtrue);
console.log(void0);
console.log(void"Welcome");
console.log(void(true));
console.log(void(0));
console.log(void("Welcome"));

All these statements would print undefined

var a = 1, b = 2;
void(a = a + b)
console.log(a);

And this would print 3. So, it is evident that, it evaluates the expressions we pass to it.

Edit: As I learn from this answer https://stackoverflow.com/a/7452352/1903116

undefined is just a global property which can be written to. For example,

console.log(undefined);
varundefined = 1;
console.log(undefined);

It prints

undefined1

So, if you want to absolutely make sure that the undefined is used, you can use void operator. As it is an operator, it cannot be overridden in javascript.

Solution 2:

void also evaluates the expression you pass to it. It doesn't just return undefined.