The difference is that some browsers allow you to overwrite the value of undefined. However, void anything always returns real undefined.
undefined = 1;
console.log(!!undefined); //true
console.log(!!void 0); //false
The difference is that some browsers allow you to overwrite the value of undefined. However, void anything always returns real undefined.
undefined = 1;
console.log(!!undefined); //true
console.log(!!void 0); //false