Benchmark: map vs for loop 1e7 iterations

Script Preparation code:

Array.prototype.map1 = function() {
	const result = []
	for(let i = 0, l = this.length; i < l; ++i) result.push(this[i])
	return result
}

Array.prototype.reverseMap = function() {
	const result = []
	for(let i = this.length; i;) { --i; result.push(this[i]) }
	return result
}

Tests:

basic map
for (let i = 1e7; i; --i) [1, 2, 3, 4, 5].map(e => e * 2)
taka map
for (let i = 1e7; i; --i) [1, 2, 3, 4, 5].map1(e => e * 2)
reverse map
for (let i = 1e7; i; --i) [1, 2, 3, 4, 5].reverseMap(e => e * 2)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
basic map
taka map
reverse map

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

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Let's break down the provided benchmark JSON and explore what's being tested.

**Benchmark Definition**
The benchmark definition is a script that prepares two custom array methods, `map1` and `reverseMap`. The purpose of these methods is to compare different approaches for iterating over an array. Here's a brief explanation:

* `map1`: This method iterates over the array using a traditional `for` loop and pushes each element to a new result array.
* `reverseMap`: This method iterates over the array in reverse order using a traditional `for` loop and pushes each element to a new result array.

**Options being compared**
The benchmark compares three different approaches:

1. **Basic Map**: The first test case uses the built-in `map()` function, which is a standard JavaScript method for iterating over an array.
2. **Custom Map (`map1`)**: The second test case uses the custom `map1` method, which is defined in the benchmark script.
3. **Reverse Custom Map (`reverseMap`)**: The third test case uses the custom `reverseMap` method.

**Pros and Cons**

* **Basic Map**: Pros:
	+ Widely supported by most browsers and JavaScript engines.
	+ Well-optimized and efficient.
Cons:
	+ May not be as fast or efficient for very large arrays due to its reliance on native browser optimizations.
* **Custom Map (`map1`)**: Pros:
	+ Can potentially offer better performance for specific use cases, as it's implemented in custom JavaScript code.
Cons:
	+ Requires additional overhead to create and execute the custom method.
	+ May not be supported by all browsers or JavaScript engines.
* **Reverse Custom Map (`reverseMap`)**: Pros:
	+ Similar to `map1`, can potentially offer better performance for specific use cases.
Cons:
	+ Reverses the iteration order, which may not always be desirable.

**Library and special JS feature**
There is no external library being used in this benchmark. However, JavaScript engines like SpiderMonkey (used by Firefox) do have some built-in features that can affect the execution speed of code, such as:

* **Just-In-Time (JIT) compilation**: Some browsers use JIT compilation to optimize performance-critical code.
* **Native code generation**: Browsers may generate native machine code for certain operations, which can impact performance.

It's worth noting that the `map()` function is a built-in JavaScript method that's optimized by most browsers and engines. The custom methods (`map1` and `reverseMap`) are designed to demonstrate potential performance differences in specific use cases.

**Other alternatives**
If you're interested in exploring alternative approaches, here are some options:

* **Using native arrays**: Instead of using custom array methods, you can try using native JavaScript arrays (e.g., `Array.prototype`) or other data structures like `Buffer` or `DataView`.
* **Using other iteration methods**: You can explore other iteration methods, such as `forEach()`, `reduce()`, or `filter()`, to compare their performance with the custom methods.
* **Using different JavaScript engines or browsers**: Experimenting with different JavaScript engines (e.g., V8, SpiderMonkey) or browsers can help you understand how specific optimizations and features affect performance.

Related benchmarks:

map vs for loop 1e7 iterations (version: 0)

Comparing performance of: basic map vs taka map vs reverse map

Created: 4 years ago by: Registered User

Jump to the latest result

basic map

taka map

reverse map

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):