Benchmark: Map vs forEach - MeasureThat.net

Tests:

Map

const createLists = (arr = []) => [
  ...arr.reduce((map, val) => {
    if (!map.has(val)) {
      map.set(val, [val]);
    } else {
      map.get(val).push(val);
    }
    return map;
  }, new Map()).values()
];
console.log(createLists([1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 0, 0, 0, 0, 0]));

AخA
 
const createLists = (arr = []) => [  ...arr.reduce((map, val) => {    if (!map.has(val)) {      map.set(val, [val]);    } else {      map.get(val).push(val);    }    return map;  }, new Map()).values()];console.log(createLists([1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 0, 0, 0, 0, 0]));

forEach

function createLists(arr = []) {
  let authors = [];
  let list = [];

  arr.forEach(item => {
    let authorIndex = authors.includes(item) ? authors.indexOf(item) : (authors.push(item) - 1);
    list[authorIndex] = list[authorIndex] || [];
    list[authorIndex].push(item);
  });

  return list;
}

console.log(createLists([1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 0, 0, 0, 0, 0]));

​x
 
function createLists(arr = []) {  let authors = [];  let list = [];​  arr.forEach(item => {    let authorIndex = authors.includes(item) ? authors.indexOf(item) : (authors.push(item) - 1);    list[authorIndex] = list[authorIndex] || [];    list[authorIndex].push(item);  });​  return list;}​console.log(createLists([1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 0, 0, 0, 0, 0]));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
Map
forEach

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36

Browser/OS: Chrome 67 on Mac OS X 10.13.4

View result in a separate tab

Test name	Executions per second
Map	16178.0 Ops/sec
forEach	17488.8 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

Benchmark Explanation

The provided JSON represents two JavaScript microbenchmarks: Map vs forEach. The benchmark compares the performance of using a Map data structure versus a traditional forEach loop to manipulate and transform an array.

Options Compared

Two options are compared:

Using a Map data structure: This approach uses the Map object to store unique values as keys, with their corresponding values stored in an array.
Using a traditional forEach loop: This approach iterates over the array using a forEach loop, pushing each value into its corresponding index in another array.

Pros and Cons of Each Approach

Map Approach
- Pros:
  - More efficient for large datasets, as it avoids duplicate values.
  - Can be more concise and expressive code.
- Cons:
  - May not be as suitable for small datasets or simple transformations.
  - Requires understanding of the Map data structure and its methods (e.g., has, get, set).
forEach Loop Approach
- Pros:
  - More familiar to many developers, who may have experience with traditional loops.
  - Can be more straightforward for small datasets or simple transformations.
- Cons:
  - May be slower and less efficient than the Map approach for large datasets.

Library Used

In this benchmark, no specific library is used. The Map data structure is a built-in JavaScript object.

Special JS Feature/Syntax

There are no special JavaScript features or syntaxes mentioned in the provided code snippets.

Other Alternatives

Alternative approaches to manipulating and transforming arrays could include:

Using reduce() method
Utilizing array methods like filter(), map(), or slice()
Employing async/await or promises for more complex transformations

These alternatives might have different performance characteristics, code readability, and maintainability compared to the Map vs forEach approach.

LLMs can make mistakes. Check important info.

**Benchmark Explanation**

The provided JSON represents two JavaScript microbenchmarks: `Map vs forEach`. The benchmark compares the performance of using a `Map` data structure versus a traditional `forEach` loop to manipulate and transform an array.

**Options Compared**

Two options are compared:

1. **Using a `Map` data structure**: This approach uses the `Map` object to store unique values as keys, with their corresponding values stored in an array.
2. **Using a traditional `forEach` loop**: This approach iterates over the array using a `forEach` loop, pushing each value into its corresponding index in another array.

**Pros and Cons of Each Approach**

* **Map Approach**
	+ Pros:
		- More efficient for large datasets, as it avoids duplicate values.
		- Can be more concise and expressive code.
	+ Cons:
		- May not be as suitable for small datasets or simple transformations.
		- Requires understanding of the `Map` data structure and its methods (e.g., `has`, `get`, `set`).
* **forEach Loop Approach**
	+ Pros:
		- More familiar to many developers, who may have experience with traditional loops.
		- Can be more straightforward for small datasets or simple transformations.
	+ Cons:
		- May be slower and less efficient than the Map approach for large datasets.

**Library Used**

In this benchmark, no specific library is used. The `Map` data structure is a built-in JavaScript object.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntaxes mentioned in the provided code snippets.

**Other Alternatives**

Alternative approaches to manipulating and transforming arrays could include:

* Using `reduce()` method
* Utilizing array methods like `filter()`, `map()`, or `slice()`
* Employing async/await or promises for more complex transformations

These alternatives might have different performance characteristics, code readability, and maintainability compared to the Map vs forEach approach.

Related benchmarks:

Map vs forEach (version: 0)

Comparing performance of: Map vs forEach

Created: 8 years ago by: Guest

Jump to the latest result

Map