Benchmark: typeof == vs typeof ===

Tests:

==
var n = 0; while(true) { n++; if(typeof n == 'number') break; }
===
var n = 0; while(true) { n++; if(typeof n === 'number') break; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
==
===

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36

Browser/OS: Chrome 115 on Windows

View result in a separate tab

Test name	Executions per second
==	810094208.0 Ops/sec
===	795439680.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one month ago):

LLMs can make mistakes. Check important info.

I'll break down the test cases and explain what's being tested, along with the pros and cons of each approach.

**Test Case Explanation**

The two test cases are measuring the performance difference between using `typeof` with a strict equality operator (`==`) versus an loose equality operator (`===`). The purpose is to compare how often the browser performs type checking when comparing `n` with `'number'`.

**Script Preparation Code and Html Preparation Code**

These fields are empty, indicating that no custom code needs to be executed before running the benchmark or rendering the HTML page for this test case.

**Test Case 1: `typeof ==`**

This test case uses a while loop that increments a variable `n` until it breaks out of the loop when `typeof n == 'number'`. This means that the browser is performing type checking on `n` to determine if it's a number. The loose equality operator (`==`) will also trigger this check, which may not be what the developer intends.

**Pros and Cons:**

Pros:

* Simple to understand and implement
* Easy to debug

Cons:

* May perform unnecessary type checks when using `==`
* Can lead to performance issues if the loop is executed frequently

**Test Case 2: `typeof ===`**

This test case uses the same while loop as before, but with `typeof n === 'number'`. This ensures that the browser performs a strict equality check on `n`, which will only trigger when both `typeof n` and `'number'` are exactly equal. This approach avoids unnecessary type checks.

**Pros and Cons:**

Pros:

* Avoids unnecessary type checks
* Ensures strict equality checking

Cons:

* May be slower due to the additional check
* More complex to implement ( requires a deeper understanding of `typeof` behavior)

**Library and Special JS Features**

None of these test cases use any external libraries or special JavaScript features.

**Other Considerations**

When writing benchmarks, it's essential to consider factors like:

* Loop iteration count: How many times the loop is executed?
* Variable size and type: Are variables allocated on the stack or heap?
* Browser engine and version: Different browsers may optimize type checking differently
* Memory pressure: Is memory allocation causing performance issues?

**Alternatives**

If you want to write similar benchmarks, consider exploring other scenarios like:

* Comparing `typeof` with string concatenation vs. using a template literal
* Testing the performance of different comparison operators (e.g., `<`, `>`, `===`)
* Measuring the impact of type checking on function call performance

When writing benchmarks, remember to keep them concise, focused, and relevant to your specific use case.

Related benchmarks:

typeof == vs typeof === (version: 0)

Comparing performance of: == vs ===

Created: one year ago by: Guest

Jump to the latest result

==

===

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one month ago):