Run results for: undefined

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.106 Safari/537.36

Browser: Chrome 83

Operating system: Mac OS X 10.15.3

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
undefined w/ type	15271710.0 Ops/sec
undefined w/o type without type check	15552280.0 Ops/sec
typeof equal to	14888440.0 Ops/sec
typeof equal to without type check	15398090.0 Ops/sec
with brackets around typeof unequal	15779730.0 Ops/sec
with brackets around typeof equal	15900120.0 Ops/sec
with brackets around typeof unequal with type check	15793000.0 Ops/sec
with brackets around typeof equal with type check	15503660.0 Ops/sec

Script Preparation code:

var obj = {};

Tests:

undefined w/ type
'undefined' !== typeof obj.d;
undefined w/o type without type check
'undefined' != typeof obj.d;
typeof equal to
typeof(obj.d) == 'undefined'
typeof equal to without type check
typeof(obj.d) === 'undefined'
with brackets around typeof unequal
typeof(obj.d) != 'undefined'
with brackets around typeof equal
typeof(obj.d) == 'undefined'
with brackets around typeof unequal with type check
typeof(obj.d) !== 'undefined'
with brackets around typeof equal with type check
typeof(obj.d) === 'undefined'