Benchmark: assigning undefined vs null

Script Preparation code:

var u = function u() {
  return undefined;
}

var n = function n() {
  return null;
}

Tests:

assigning null
var a = null;
assigning undefined
var a = undefined;
not assigning anything
var a;
return null
n();
return undefined
u();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
assigning null
assigning undefined
not assigning anything
return null
return undefined

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

I'll explain the benchmark and its options in detail.

**Benchmark Definition**

The benchmark definition provided is a simple JavaScript script that defines two functions, `u` and `n`, which return `undefined` and `null`, respectively. The script also includes assignment statements to test different scenarios.

**Script Preparation Code**

```javascript
var u = function u() {
  return undefined;
}

var n = function n() {
  return null;
}
```

This code defines two functions, `u` and `n`, which can be called directly or assigned to variables. The `u` function returns `undefined`, while the `n` function returns `null`.

**Html Preparation Code**

There is no HTML preparation code provided.

**Individual Test Cases**

The benchmark includes six test cases:

1. **Assigning null**: `var a = null;`
2. **Assigning undefined**: `var a = undefined;`
3. **Not assigning anything**: `var a;`
4. **Returning null**: `n();`
5. **Returning undefined**: `u();`

Each test case is defined by a `Benchmark Definition` string that specifies the assignment statement or function call to be executed.

**Options Compared**

The benchmark compares different options:

1. Assigning `null` vs `undefined`: This option tests how browsers handle assignments of `null` and `undefined`.
2. Not assigning anything: This option tests the performance impact of not assigning a value to a variable.
3. Returning null vs returning undefined: This option tests how browsers handle function returns with `null` vs `undefined`.

**Pros and Cons**

Here are some pros and cons for each option:

1. **Assigning null vs undefined**:
	* Pros: This test helps identify performance differences between assigning `null` and `undefined`.
	* Cons: This test may not be relevant in most scenarios where the distinction between `null` and `undefined` is important.
2. **Not assigning anything**:
	* Pros: This test helps identify performance implications of uninitialized variables.
	* Cons: This test may not be representative of real-world usage, as variables are usually assigned values.
3. **Returning null vs returning undefined**:
	* Pros: This test helps identify performance differences between returning `null` and `undefined`.
	* Cons: This test may not be relevant in most scenarios where the distinction between `null` and `undefined` is important.

**Library**

There are no libraries mentioned in the benchmark definition. However, it's worth noting that some browsers (e.g., Firefox) use the `Object` prototype to determine whether a variable is `null`, `undefined`, or an object. This might be relevant when testing assignments with `null` and `undefined`.

**Special JS Feature**

There are no special JavaScript features mentioned in the benchmark definition.

**Alternatives**

Some alternative approaches for benchmarks like this one could include:

1. **Benchmarking memory allocation**: Instead of assigning values to variables, test how browsers allocate memory for objects.
2. **Benchmarking object creation**: Test how browsers create objects and compare performance implications.
3. **Benchmarking string manipulation**: Compare the performance of different string manipulation techniques, such as concatenation vs interpolation.

These alternative approaches could provide more comprehensive insights into browser performance and optimization.

Related benchmarks:

assigning undefined vs null (version: 0)

Comparing performance of: assigning null vs assigning undefined vs not assigning anything vs return null vs return undefined

Created: 7 years ago by: Registered User

Jump to the latest result

assigning null

assigning undefined

not assigning anything

return null

return undefined

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):