"Type of undefined" vs "=== undefined" (v18)

Revision 18 of this benchmark created on

Setup

var values = [1, true, "c", [],
    {},
    undefined];
    
    var vars = [];
    for (var i; i < 1000; i++) {
    
      vars.push(values[Math.floor(Math.random() * values.length)]);
    }
    
    var u = undefined;

Test runner

Ready to run.

Testing in
TestOps/sec
typeof undefined
for (var key in vars) {

  typeof vars[key] == 'undefined';
}
ready
=== undefined
for (var key in vars) {

  vars[key] === undefined;
}
ready
=== undefined(local)
for (var key in vars) {

  vars[key] === u;
}
ready
void 0
for (var key in vars) {

  vars[key] === void 0;
}
ready
void null
for (var key in vars) {

  vars[key] === void null;
}
ready

Revisions

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