Benchmark: typeof x === 'number' vs Number.isNaN(x)

Tests:

typeof
typeof 5 === 'number'
Number.isNaN
Number.isNaN(5)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typeof
Number.isNaN

Fastest: N/A

Slowest: N/A

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

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Let's break down the benchmark and explain what's being tested.

**Overview**

The MeasureThat.net website provides a platform for users to create and run JavaScript microbenchmarks. The provided JSON represents a benchmark that tests two different approaches to check if a value is a number in JavaScript: using the `typeof` operator versus the `Number.isNaN()` function.

**Options Being Compared**

There are two options being compared:

1. **typeof x === 'number'**: This approach uses the `typeof` operator to check if a variable `x` is of type `'number'`. The `typeof` operator returns a string indicating the type of the value, and in this case, it will return `'number'` for numeric values.
2. **Number.isNaN(x)**: This approach uses the `Number.isNaN()` function to check if a variable `x` is not a number (i.e., NaN). The `Number.isNaN()` function returns a boolean value indicating whether the input value is NaN.

**Pros and Cons**

Here are some pros and cons of each approach:

**typeof x === 'number'**

Pros:

* Simple and concise syntax
* Works for non-numeric values as well (e.g., strings, booleans)

Cons:

* Can be slower than `Number.isNaN()` because it involves a string comparison
* May not work correctly in some cases, such as when dealing with NaN values

**Number.isNaN(x)**

Pros:

* Faster and more efficient than using `typeof`
* Handles NaN values correctly

Cons:

* More verbose syntax (requires the function call)
* May be less readable for some developers

**Library**

In this benchmark, the `Number` object is used, which is a built-in JavaScript object that provides various number-related functions and properties. The `isNaN()` method is a property of the `Number` object, which returns a boolean value indicating whether the input value is NaN.

**Special JS Feature or Syntax**

There is no special JS feature or syntax being tested in this benchmark. It's purely a matter of comparing two different approaches to check if a value is a number.

**Other Alternatives**

If you need to compare these approaches, here are some alternatives:

* You could also use the `Number()` function instead of `typeof x === 'number'`. The `Number()` function converts its argument to a number, and returns 0 if it's not possible (e.g., for strings).
* Another alternative is to use the `instanceof` operator, which can be used to check if an object is an instance of the `Number` constructor.

Here's some example code that demonstrates these alternatives:
```javascript
// Using Number()
if (isNaN(Number(5))) {
  console.log('Not a number');
}

// Using instanceof
if (!(5 instanceof Number)) {
  console.log('Not a number');
}
```
Note that these alternatives may have different performance characteristics and readability trade-offs compared to the original approaches.

Related benchmarks:

typeof x === 'number' vs Number.isNaN(x) (version: 0)

check what is faster

Comparing performance of: typeof vs Number.isNaN

Created: 2 years ago by: Guest

Jump to the latest result

typeof

Number.isNaN

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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