Benchmark: void vs typeof - MeasureThat.net

Script Preparation code:

var value = 2;

Tests:

typeof
typeof value !== 'undefined'
void 0
value !== void 0

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typeof
void 0

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Whale/3.5.3.2 Safari/537.36

Browser/OS: Chrome 120 on Linux

View result in a separate tab

Test name	Executions per second
typeof	10891501.0 Ops/sec
void 0	10590432.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in this benchmark and the pros and cons of each approach.

**Benchmark Definition**

The benchmark definition is a JSON object that defines the benchmark's name, description, script preparation code, and HTML preparation code. However, there are no options to compare in this case.

Instead, we have two individual test cases:

1. `typeof value !== 'undefined'`
2. `value !== void 0`

**What are `typeof` and `void 0`?**

* `typeof` is a JavaScript operator that returns the data type of a variable or expression. In this case, it's used to check if the `value` variable has been initialized.
* `void 0` is an older syntax for checking if a value is not null or undefined (equivalent to `typeof value !== 'undefined'`). The `void` keyword is used as a "null coalescing" operator in this context.

**Options comparison**

The options being compared are:

1. `typeof value !== 'undefined'`
2. `value !== void 0`

Both expressions achieve the same result: checking if `value` has been initialized. However, there's a subtle difference:

* Using `typeof` is more explicit and readable.
* Using `void 0` is older syntax that was used in JavaScript before the `typeof` operator became widely adopted.

**Pros and Cons**

Pros of using `typeof`:

* More modern and widely adopted
* Easier to read and understand for new developers

Cons of using `typeof`:

* May be slower due to the overhead of calling an operator function

Pros of using `void 0`:

* Older syntax that was used in earlier versions of JavaScript
* May be faster due to caching effects (although this is largely mitigated by modern JavaScript engines)

Cons of using `void 0`:

* Less readable and more prone to typos or mistakes
* Not as widely adopted, making it less familiar to new developers

**Other considerations**

In general, when deciding between these two options, consider the following:

* If you're writing new code, use `typeof`.
* If you're working with legacy code or need to support older browsers, use `void 0`.

Keep in mind that both expressions have equivalent results and are widely supported.

**Other alternatives**

If you want to explore other ways of checking if a value is initialized, consider the following options:

1. Using an explicit `if` statement: `if (value !== null && value !== undefined) { ... }`
2. Using the optional chaining operator (`?.`): `value?.toString()`
3. Using a conditional expression (`?:`): `(value ? 'initialized' : 'not initialized')`

However, these alternatives may have their own trade-offs and may not be as widely supported or efficient as the original two options.

Related benchmarks:

void vs typeof (version: 0)

Comparing performance of: typeof vs void 0

Created: 4 years ago by: Guest

Jump to the latest result

typeof

void 0

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):