Benchmark: ES6 Map Merge vs forEach

Script Preparation code:

const entries1 = [];
const entries2 = [];
for (let i = 0; i < 1000; i++) {
  entries1[i] = [i , i];
}
for (let i = 0; i < 1000; i++) {
  entries2[i] = [i + 500, i + 600];
}
const pathSegmentMap = new Map(entries1);
const newSegmentMap = new Map(entries2);

Tests:

Merge
const entries1 = []; const entries2 = []; for (let i = 0; i < 1000; i++) { entries1[i] = [i , i]; } for (let i = 0; i < 1000; i++) { entries2[i] = [i + 500, i + 600]; } const pathSegmentMap = new Map(entries1); const newSegmentMap = new Map(entries2); const mergeMap = new Map([...pathSegmentMap, ...newSegmentMap]);
Loop
const entries1 = []; const entries2 = []; for (let i = 0; i < 1000; i++) { entries1[i] = [i , i]; } for (let i = 0; i < 1000; i++) { entries2[i] = [i + 500, i + 600]; } const pathSegmentMap = new Map(entries1); const newSegmentMap = new Map(entries2); newSegmentMap.forEach((value, key) => { pathSegmentMap.set(key, value); });

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Loop

10K/s

Merge

7K/s

Fastest: Loop (1.6x faster)

View exact numbers

✓ Loop: 10,383 ops/sec
• Merge: 6,598 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Merge
Loop

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/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Loop

16K/s

Merge

10K/s

View exact numbers

Test name	Executions per second
✓ Loop	16,276 Ops/sec
Merge	10,202 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 benchmark definition and test cases to understand what's being tested.

**Benchmark Definition**

The benchmark is defined in JSON format, which contains information about the test case:

* `Name`: The name of the benchmark, "ES6 Map Merge vs forEach".
* `Description`: An empty string, indicating that no description is provided.
* `Script Preparation Code`: A JavaScript code snippet that creates two arrays, `entries1` and `entries2`, each with 1000 elements. The arrays are populated with nested arrays containing two values each.
* `Html Preparation Code`: An empty string, indicating that no HTML preparation is required.

**Test Cases**

There are two test cases:

1. **Merge**:
	* `Benchmark Definition`: A JavaScript code snippet that creates a new map by merging two existing maps, `pathSegmentMap` and `newSegmentMap`, using the spread operator (`...`).
2. **Loop**:
	* `Benchmark Definition`: A JavaScript code snippet that iterates over the elements of `newSegmentMap` and updates the values in `pathSegmentMap` using a loop.

**What's being tested**

The benchmark is testing the performance difference between two approaches:

1. **Merge**: Using the spread operator to merge two maps.
2. **Loop**: Iterating over the elements of one map and updating another map using a loop.

**Pros and Cons**

* **Merge**:
	+ Pros:
		- Concise and readable syntax.
		- Efficient, as it avoids the need for explicit looping.
	+ Cons:
		- May have performance overhead due to the use of the spread operator.
		- Can be slower than manual iteration in some cases (e.g., when dealing with large datasets).
* **Loop**:
	+ Pros:
		- Can be faster, as it avoids the overhead of the spread operator.
		- Can be more controlled and predictable.
	+ Cons:
		- More verbose syntax can make the code harder to read.
		- Requires explicit looping, which can lead to errors if not done correctly.

**Libraries**

The benchmark uses JavaScript's built-in `Map` data structure, which is a dictionary-like object that stores key-value pairs. No external libraries are required for this benchmark.

**Special JS features/syntax**

The benchmark does not use any special JavaScript features or syntax. It only relies on standard JavaScript constructs and methods.

**Alternatives**

Other alternatives to test the performance of merging maps include:

* Using `Object.assign()` instead of the spread operator.
* Using a library like Lodash's `merge` function.
* Testing with manual iteration using a `for...in` loop or a `forEach` loop (similar to the "Loop" test case).

Keep in mind that the choice of approach depends on the specific requirements and constraints of the project.

ES6 Map Merge vs forEach (version: 0) Benchmark.js

Comparing performance of: `Merge vs Loop`

Created: 7 years ago by: Guest

Go to the latest result

Merge

Loop

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

ES6 Map Merge vs forEach (version: 0) Benchmark.js

Comparing performance of: Merge vs Loop

Created: 7 years ago by: Guest

Go to the latest result

Merge

Loop

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `Merge vs Loop`