Benchmark: Map. foreach - MeasureThat.net

Script Preparation code:

const originalMap = new Map(Array.from({ length: 1000000 }, (_, i) => [i, i]));

Tests:

forEach
const originalMap = new Map(Array.from({ length: 1000000 }, (_, i) => [i, i])); const newMap = new Map(); originalMap.forEach((value, key) => { newMap.set(key, value * 2); }); return newMap;
Array
const originalMap = new Map(Array.from({ length: 1000000 }, (_, i) => [i, i])); const newMap = new Map( Array.from(originalMap.entries(), ([key, value]) => [key, value * 2]) );

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
Array

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36

Browser/OS: Chrome 128 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
forEach	6.0 Ops/sec
Array	5.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

The provided JSON represents a benchmark definition, which is a set of rules that define how to create and run a benchmark. The key aspects of this definition are:

1. **Script Preparation Code**: This code snippet creates an initial data structure for the benchmark. In this case, it creates a large Map with 1 million entries.
2. **Html Preparation Code**: There is no HTML preparation code provided, which means that the browser's default HTML content will be used.

**Individual Test Cases**

There are two individual test cases:

### Test Case 1: `forEach`

This test case involves iterating over the original Map using the `forEach` method and updating a new Map with transformed values. The benchmark definition is:
```javascript
const originalMap = new Map(Array.from({ length: 1000000 }, (_, i) => [i, i]));
const newMap = new Map();
originalMap.forEach((value, key) => {
  newMap.set(key, value * 2);
});
return newMap;
```
This test case measures the performance of using the `forEach` method to iterate over a large dataset.

### Test Case 2: `Array`

This test case uses the spread operator (`...`) and the `Array.from()` method to create a new Array from an array of Map entries, and then iterates over this new Array. The benchmark definition is:
```javascript
const originalMap = new Map(Array.from({ length: 1000000 }, (_, i) => [i, i]));
const newMap = new Map(
  Array.from(originalMap.entries(), ([key, value]) => [key, value * 2])
);
```
This test case measures the performance of using the spread operator and `Array.from()` to create a new Array from an array of Map entries.

**Options Compared**

The two test cases compare the following options:

1. **Iterating over a large dataset**: Both tests involve iterating over a large dataset, but using different methods.
2. **Creating a new data structure**: Both tests create a new data structure (a new Map), but using different approaches.

**Pros and Cons of Each Approach**

Here are some pros and cons of each approach:

1. `forEach`:
	* Pros:
		+ Easier to read and understand for some developers.
		+ Less memory overhead since it doesn't create a new array or object.
	* Cons:
		+ May be slower due to the overhead of calling the `forEach()` method.
2. `Array`:
	* Pros:
		+ Faster due to the optimized performance of using an Array.
		+ More memory-efficient since it uses an existing data structure (the original Map).
	* Cons:
		+ More complex code, which may be harder to understand for some developers.

**Library Usage**

In this benchmark, the `Map` object is used from the JavaScript standard library. The `Array.from()` method and spread operator are also part of the standard library.

**Special JS Features or Syntax**

There are no special features or syntax mentioned in the benchmark definitions. However, it's worth noting that some modern browsers have optimized support for certain features like `Map.forEach()` and `Array.prototype.map()`.

**Other Alternatives**

If you want to test other approaches, here are a few alternatives:

1. Use `for...of` loop instead of `forEach()`.
2. Use `Object.entries()` and `Object.fromEntries()` methods.
3. Use a custom iterator or generator function.
4. Compare the performance of using different data structures, such as arrays or linked lists.

Keep in mind that these alternatives may not be directly comparable to the original benchmark definitions, so you'll need to modify them accordingly.

Related benchmarks:

Map. foreach (version: 0)

Comparing performance of: forEach vs Array

Created: one year ago by: Guest

Jump to the latest result

forEach

Array

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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