window.obj = undefined
window.obj === undefined
typeof window.obj === 'undefined'
window.obj == undefined
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
equality | |
typeof | |
double-equal |
Test name | Executions per second |
---|---|
equality | 5584100.0 Ops/sec |
typeof | 5586317.5 Ops/sec |
double-equal | 5638271.5 Ops/sec |
Let's break down the provided benchmark and explain what's being tested, compared, and their pros and cons.
Benchmark Overview
The test is designed to compare three approaches for checking if window.obj
is undefined
:
===
)typeof
operator with 'undefined'
==
)Library and Special JS Features
In this benchmark, the only library being used is the built-in JavaScript language features.
No special JavaScript features or syntax are being tested in this benchmark.
Approaches Compared
===
)===
.typeof
Operator with 'undefined'
typeof
operator, comparing it to 'undefined'
.==
)Results
The benchmark results show the number of executions per second for each test case on Firefox 115. The order of execution speed is:
typeof
Operator with 'undefined'
===
)==
)This suggests that the typeof
operator with 'undefined'
is the fastest approach, followed closely by the equality check.
Alternatives
If you need to optimize this type of comparison, consider the following alternatives:
isEqual
) that can be optimized for performance.===
operator with strict equality (strictEqual
) which is faster than the traditional equality check.Keep in mind that these alternatives may require additional expertise and may not be necessary for most use cases. The original approach of using typeof
or equality checks will likely suffice for most applications.