Run results for: undefined

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36

Browser: Chrome 80

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
undefined w/ type	9327039.0 Ops/sec
undefined w/o type without type check	9393496.0 Ops/sec
typeof equal to	9416017.0 Ops/sec
typeof equal to without type check	9434654.0 Ops/sec
with brackets around typeof unequal	9417362.0 Ops/sec
with brackets around typeof equal	9439816.0 Ops/sec
with brackets around typeof unequal with type check	9405951.0 Ops/sec
with brackets around typeof equal with type check	9397434.0 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'