Benchmark: forEach.Map.set() vs new Map()

Script Preparation code:

var chars = [...'abcdefghijklmnopqrstuvwxyz'];

function setIndividually(arr) {
  return arr.reduce((acc, cur) => {
    acc.set(cur, { char: cur });

    return acc;
  }, new Map());
}

function createWithProperties(arr) {
  const props = arr.map(elem => [elem, { char: elem }]);

  return new Map(props);
}

Tests:

Set individually
var foo = setIndividually(chars);
Create with properties
var bar = createWithProperties(chars);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Set individually
Create with properties

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Windows

View result in a separate tab

Test name	Executions per second
Set individually	312072.2 Ops/sec
Create with properties	266785.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The test case compares two approaches to create and populate a Map data structure in JavaScript:

1. `setIndividually(arr)`: This function creates a Map by iteratively setting individual key-value pairs using the `set()` method.
2. `createWithProperties(arr)`: This function creates a Map by passing an array of key-value pairs directly to the constructor.

**What's being compared**

The test case compares the performance (in terms of executions per second) of these two approaches on a sample dataset (`chars`) containing 26 characters.

**Pros and Cons**

1. `setIndividually(arr)`:
	* Pros:
		+ More explicit and controlled way of setting key-value pairs.
		+ Could be more suitable for certain use cases where individual settings are needed.
	* Cons:
		+ Might lead to slower performance due to the overhead of repeated `set()` calls.
2. `createWithProperties(arr)`:
	* Pros:
		+ Potentially faster since it uses a single constructor call with an array of key-value pairs.
		+ More concise and easier to read.
	* Cons:
		+ Assumes that the properties can be passed directly in the order they should be set, which might not always be the case.

**Library/Tool usage**

There is no explicit library or tool being used in this benchmark. However, it's worth noting that `Map` is a built-in JavaScript data structure introduced in ECMAScript 2015 (ES6).

**Special JS feature/syntax**

No special JavaScript features or syntax are mentioned. The code only uses standard JavaScript features like `Map`, arrays, and arrow functions.

**Other alternatives**

Alternative approaches to create and populate a Map could include:

1. Using the `Object.create()` method to create an object with initial properties.
2. Using the `Array.prototype.map()` method to create a new array of key-value pairs.
3. Using a library like Lodash or Ramda for functional programming.

However, these alternatives might not be as concise or efficient as the `createWithProperties(arr)` approach used in this benchmark.

Related benchmarks:

forEach.Map.set() vs new Map() (version: 0)

Comparing performance of: Set individually vs Create with properties

Created: 2 years ago by: Guest

Jump to the latest result

Set individually

Create with properties

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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