Benchmark: map iteration 2 - MeasureThat.net

Script Preparation code:

var obj = {
  a: 1,
  b: 2,
  c: 3,
  d: 4,
  e: 5,
  f: 6,
  g: 7,
  h: 8,
  i: 9,
  j: 10,
  k: 11,
  l: 12,
  m: 13,
  n: 14,
  o: 15,
  p: 16,
  q: 17,
  r: 18,
  s: 19,
  t: 20,
  u: 21,
  v: 22,
  w: 23,
  x: 24,
  y: 25,
  z: 26
};
var map = new Map(Object.entries(obj));

Tests:

entries()
let total = 0; for (const [key, value] of map) { total += value; }
for of
let total = 0, key, value; for ([key, value] of map.entries()) { total += value; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
entries()
for of

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.110 Safari/537.36

Browser/OS: Chrome 96 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
entries()	3427626.0 Ops/sec
for of	3425302.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark JSON and explain what's being tested.

**Benchmark Definition**
The `map iteration 2` benchmark is testing the performance of iterating over a Map object using two different approaches: `entries()` and `for of`.

**Script Preparation Code**
The script preparation code creates a large Map object, `obj`, with 26 entries (keys-value pairs) and assigns it to a variable `map`. The `Map` constructor is used to create the map from an array of key-value pairs created using `Object.entries(obj)`.

**Html Preparation Code**
There is no HTML preparation code provided for this benchmark.

**Individual Test Cases**

### 1. `entries()`

This test case uses the `entries()` method to iterate over the Map object and calculates the sum of all values in the map.

**Library Used:** None

**Pros:**

* Efficient way to iterate over a Map, as it returns an iterator that yields key-value pairs.
* Can be faster than other methods for large datasets.

**Cons:**

* May not be suitable for older browsers or systems that don't support modern iterators.
* Can be less readable and maintainable compared to traditional `for` loops.

### 2. `for of`

This test case uses a traditional `for...of` loop to iterate over the Map object's entries, also calculating the sum of all values in the map.

**Library Used:** None

**Pros:**

* More readable and maintainable than using iterators or `entries()` methods.
* Can be suitable for older browsers or systems that don't support modern iterators.
* Provides more control over iteration order (if needed).

**Cons:**

* May not be as efficient as using `entries()` or other iterator-based approaches for large datasets.

**Special JS Feature/Syntax:** None mentioned in the provided benchmark.

**Other Alternatives:**

1. **Array.prototype.forEach()**: This method can also be used to iterate over a Map's entries, although it may have performance implications for very large datasets.
2. **Map.entries().forEach()**: Similar to `Array.prototype.forEach()`, but using the Map's iterator-based approach.

**Benchmark Results**
The latest benchmark results show that the `entries()` approach is slightly faster than the traditional `for...of` loop, with an execution rate of 3427626.0 executions per second compared to 3425302.5 executions per second for the `for of` loop on a Mac OS X 10.15.7 system running Chrome 96.

In summary, this benchmark is testing the performance of two common ways to iterate over a Map object in JavaScript: using the `entries()` method and traditional `for...of` loops. The results indicate that `entries()` may be slightly faster for this specific use case.

Related benchmarks:

map iteration 2 (version: 0)

Comparing performance of: entries() vs for of

Created: 2 years ago by: Guest

Jump to the latest result

entries()

for of

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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