Benchmark: Map Value Iteration

Script Preparation code:

var map = new Map(Object.entries({
  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 values = Array.from(map.values());
var entries = Array.from(map.entries());

Tests:

map.values()
let total = 0; for(const i of map.values()) total += i;
values array
let total = 0; for(const i of values) total += i;
entries array
let total = 0; for(const [k, i] of entries) total += i;
values.values()
let total = 0; for(const i of values.values()) total += i;
values length-based
let total = 0; const length = values.length; for(let i = 0; i < length; i++) total += values[i];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map.values()
values array
entries array
values.values()
values length-based

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 15 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
map.values()	10853819.0 Ops/sec
values array	23785446.0 Ops/sec
entries array	17294300.0 Ops/sec
values.values()	23869054.0 Ops/sec
values length-based	15343110.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll dive into the explanation of the provided benchmark.

**Benchmark Overview**

The benchmark, named "Map Value Iteration," tests various approaches to iterate over a Map data structure in JavaScript. A Map is an object that stores key-value pairs. In this benchmark, we create a large Map with 26 entries and then test different ways to iterate over its values.

**Comparison of Approaches**

1. **`map.values()`**: This approach uses the built-in `values()` method of the Map object to get an iterator over its values. The benchmark measures how many executions per second this method can handle.
	* Pros: Simple, efficient, and well-supported by most JavaScript engines.
	* Cons: May not be suitable for very large Maps or performance-critical applications.
2. **`Array.from(map.values())`**: This approach uses the `Array.from()` method to create an array from the values iterator returned by `map.values()`. The benchmark measures how many executions per second this method can handle.
	* Pros: Similar to the previous approach but with more overhead due to the extra step of creating an array. However, it might still be suitable for smaller Maps or applications where performance isn't critical.
	* Cons: Adds unnecessary complexity and overhead compared to the first approach.
3. **`for...of` loop over `values` array**: This approach uses a traditional `for...of` loop to iterate over an array created from the values iterator returned by `map.values()`. The benchmark measures how many executions per second this method can handle.
	* Pros: Can be more efficient than the first two approaches for very large Maps, as it avoids the overhead of creating an array. However, it requires a traditional loop and may not be suitable for smaller Maps or applications where readability isn't important.
	* Cons: May have higher overhead due to the need for an explicit loop, which can make the code less readable.
4. **`values.length` and `for...of` loop**: This approach uses the length property of the values iterator to iterate over the Map's values. The benchmark measures how many executions per second this method can handle.
	* Pros: Can be more efficient than the first three approaches for very large Maps, as it avoids creating an array or using a traditional loop. However, it requires manual indexing and may not be suitable for smaller Maps or applications where readability isn't important.
	* Cons: May have higher overhead due to the need for manual indexing and loop control.

**Library Usage**

There is no explicit library usage mentioned in this benchmark. The JavaScript engine's built-in functionality is used to create and iterate over the Map data structure.

**Special JS Feature/Syntax**

The benchmark doesn't use any special JavaScript features or syntax beyond what's standard for modern JavaScript engines. However, it does utilize some older syntax, such as the `Object.entries()` method (introduced in ECMAScript 2015) to create the initial Map object.

**Other Alternatives**

If you need to iterate over a large Map data structure in JavaScript, other alternatives might include:

1. **`for...in` loop**: This approach can be used with Map iterators as well, although it may not be the most efficient or readable option.
2. **Third-party libraries or frameworks**: Some libraries or frameworks, like React or Angular, provide optimized iteration over Maps for specific use cases.

Keep in mind that the performance differences between these approaches might be negligible for smaller Maps or applications where performance isn't critical. However, for very large Maps or performance-critical applications, using a built-in `values()` method and minimizing overhead can lead to significant improvements.

Related benchmarks:

Map Value Iteration (version: 0)

Comparing performance of: map.values() vs values array vs entries array vs values.values() vs values length-based

Created: 3 years ago by: Registered User

Jump to the latest result

map.values()

values array

entries array

values.values()

values length-based

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):