Benchmark: fill array with value: map(callback) vs fill(value)

Script Preparation code:

var array = (new Array(10000)).map((e, i) => ({t: i}));

Tests:

.map(callback)
const result = array.map(() => true);
.fill(value)
const result = new Array(array.length).fill(true);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
.map(callback)
.fill(value)

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36

Browser/OS: Chrome 83 on Linux

View result in a separate tab

Test name	Executions per second
.map(callback)	21477.0 Ops/sec
.fill(value)	14152.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases to understand what's being tested.

**Benchmark Definition**

The benchmark defines two different methods for filling an array with values: `map(callback)` and `fill(value)`. The `map()` method applies a callback function to each element of the array, while the `fill()` method sets all elements of the array to the same value.

**Options Compared**

The two options are compared in terms of their performance. The benchmark measures how many executions per second (ExecutionsPerSecond) each option produces.

**Pros and Cons**

* **`map(callback)`**:
	+ Pros: Can be more flexible, as it allows for a callback function to transform the values in the array.
	+ Cons: May be slower due to the overhead of applying the callback function to each element.
* **`fill(value)`**:
	+ Pros: Typically faster, as it sets all elements to the same value without any transformations.
	+ Cons: Less flexible, as it requires setting a fixed value for all elements.

In general, `map()` is useful when you need to transform or process individual elements in an array, while `fill()` is suitable when you just need to set all elements to the same value.

**Library and Purpose**

There is no specific library mentioned in this benchmark. However, it's worth noting that some JavaScript engines or browsers might have internal optimizations or features that could impact performance for these methods.

**Special JS Features**

The benchmark does not use any special JavaScript features, such as async/await, promise chains, or decorators. The code snippets are straightforward and demonstrate the basic usage of `map()` and `fill()`.

**Alternatives**

If you're interested in exploring alternative approaches to filling an array with values, here are a few options:

* **Using `Array.prototype.forEach()`**: This method iterates over the array, executing the callback function for each element.
* **Using `Array.from()`**: This method creates a new array by iterating over an iterable (e.g., a string or another array) and creating elements from it.

Keep in mind that these alternatives might not provide the same performance characteristics as `map()` and `fill()`, but they can be useful in different situations.

Related benchmarks:

fill array with value: map(callback) vs fill(value) (version: 0)

Comparing performance of: .map(callback) vs .fill(value)

Created: 3 years ago by: Guest

Jump to the latest result

.map(callback)

.fill(value)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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