Benchmark: Map and Filter vs forEach

Script Preparation code:

var jobIds = [1, 2, 3, 4, 5]
var jobs = {
  1: { status: 2 },
  2: { status: 1 },
  3: { status: 3 },
  4: { status: 2 },
  5: { status: 3 }
}

Tests:

map and filter
var activeJobs = jobIds.map(id => jobs[id]).filter(job => job.status !== 3)
forEach
var activeJobs = [] jobIds.forEach(id => { var job = jobs[id] if (job.status !== 3) activeJobs.push(job) })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map and filter
forEach

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

I'll break down the benchmark and explain what's being tested, compared options, pros and cons, library usage, special JS features or syntax, and alternative approaches.

**Benchmark Purpose**

The test measures the performance difference between two approaches for filtering an array of job IDs: `map` and `filter`, versus using a traditional loop with `forEach`. The benchmark aims to identify which approach is faster and more efficient.

**Options Compared**

There are two options being compared:

1. **Map and Filter**: This approach uses the built-in `map` method to create a new array of job objects based on the filtered conditions, followed by the `filter` method to remove jobs with status 3.
2. **forEach Loop**: This approach uses a traditional loop with `forEach` to iterate through each job ID, creating a new object for each job and pushing it into an array if its status is not 3.

**Pros and Cons**

* **Map and Filter**:
	+ Pros: More concise and readable code, less chance of off-by-one errors.
	+ Cons: Can be slower due to the creation of a new array.
* **forEach Loop**:
	+ Pros: Faster execution time, as it avoids creating a new array.
	+ Cons: More verbose code, more prone to off-by-one errors.

**Library Usage**

The `map` and `filter` methods are built-in JavaScript Array.prototype methods. They are part of the ECMAScript standard and do not require any additional libraries or dependencies.

**Special JS Feature or Syntax**

There is no special JavaScript feature or syntax being used in this benchmark. It's a basic demonstration of two common array manipulation techniques in JavaScript.

**Alternative Approaches**

Other approaches that could be considered for filtering an array include:

* Using `reduce` to create a new array.
* Using a function with `every` method to filter the array.
* Using a library like Lodash, which provides a `filter` function as part of its utility belt.
* Using a different programming language or framework that might have built-in filtering capabilities.

**Benchmark Preparation Code**

The preparation code is used to set up the test environment. In this case:

* The `jobIds` array is defined with some sample data.
* A `jobs` object is created with corresponding job objects for each ID in `jobIds`.
* The two benchmark definitions are provided as strings, which will be executed by the test runner.

**Individual Test Cases**

Each test case defines a specific benchmarking scenario. In this case:

* The first test case (`map and filter`) uses the `map` and `filter` methods to create a new array of active jobs.
* The second test case (`forEach`) uses a traditional loop with `forEach` to iterate through each job ID, creating a new object for each job and pushing it into an array if its status is not 3.

**Latest Benchmark Result**

The latest benchmark result provides the execution time for each test case on a specific device (Chrome 90 on Windows). The results are displayed in the format of `ExecutionsPerSecond`, which represents the number of times the code was executed per second.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.93 Safari/537.36

Browser/OS: Chrome 90 on Windows

View result in a separate tab

Test name	Executions per second
map and filter	1707840.0 Ops/sec
forEach	1512166.1 Ops/sec

Related benchmarks:

Map and Filter vs forEach (version: 1)

Comparing performance of: map and filter vs forEach

Created: 6 years ago by: Registered User

Jump to the latest result

map and filter

forEach

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):