Benchmark: Map.foreach vs Map.for..of with func

Script Preparation code:

var mapV = new Map([[1, 1], [2, 1],[3, 1],[4, 1],[5, 1],[6, 1],[7, 1],[8, 1],[9, 1],[10, 1],[11, 1],[12, 1],[13, 1],[14, 1],[15, 1],[16, 1],[17, 1],[18, 1],[19, 1],[20, 1],[21, 1],[22, 1],[23, 1],[24, 1],[25, 1]]);

Tests:

foreach
mapV.forEach(function(value, key) { console.info(value + key); });
for..of
for (var [key, value] of mapV) { console.info(value + key); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for..of

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36

Browser/OS: Chrome 140 on Windows

View result in a separate tab

Test name	Executions per second
foreach	9163.4 Ops/sec
for..of	7938.0 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.

The provided JSON represents a benchmark test that compares the performance of two approaches for iterating over a Map object in JavaScript: `Map.forEach` and `Map.for..of with func`.

**Test Comparison**

In this test, we have two individual test cases:

1. **foreach**: This test uses the traditional `forEach` method to iterate over the Map object.
2. **for..of**: This test uses the new `for...of` loop syntax, which is designed for iterating over iterable objects like Maps.

**Options Compared**

The two options being compared are:

* **Traditional `forEach`**: This approach uses a callback function to process each item in the Map.
* **New `for...of` with func**: This approach uses a new syntax for iterating over an iterable object, which is designed to be more efficient and readable.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* **Traditional `forEach`**:
	+ Pros: Wide support across older browsers and versions.
	+ Cons: Can be slower than the new `for...of` syntax due to the overhead of function calls.
* **New `for...of` with func**:
	+ Pros: Faster performance, more concise code, better support for modern browsers and JavaScript engines.
	+ Cons: May not work in older browsers or versions that don't support the new syntax.

**Library**

None of the test cases use any external libraries. The Map object is a built-in JavaScript data structure.

**Special JS Feature/Syntax**

The `for...of` loop syntax is a relatively recent addition to JavaScript, introduced in ECMAScript 2015 (ES6). It's designed for iterating over iterable objects like Maps, Sets, and arrays.

**Benchmark Preparation Code**

The provided preparation code creates a large Map object with 30 key-value pairs. This Map object is used as the input for both test cases.

**Other Alternatives**

If you're looking for alternative approaches to iterate over a Map object in JavaScript, here are some options:

* **`Array.prototype.forEach.call(map)`**: This approach uses the `forEach` method on an array wrapper around the Map object.
* **`map.entries()`**: This approach uses the `entries()` method on the Map object to get an iterator over its key-value pairs.
* **Manual iteration using a loop**: You can also write a custom loop to iterate over the Map object, but this is generally considered less readable and less efficient than the other options.

Related benchmarks:

Map.foreach vs Map.for..of with func (version: 0)

Compare loop performance

Comparing performance of: foreach vs for..of

Created: 4 years ago by: Guest

Jump to the latest result

foreach

for..of

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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