Benchmark: Array.find vs. Map.get

Array.find vs. Map.get (version: 5)

Test the performance of Array.find vs. Map.get, with various array sizes, and with/without conversion from array to map

Comparing performance of: Array.find, 10 000 elements vs Map.get, 10 000 elements vs Array.find, 1 000 000 elements vs Map.get, 1 000 000 elements vs Array to Map + Map.get, 1 lookup vs Array to Map + Map.get, 10 lookups vs Array to Map + Map.get, 100 lookups vs Array.find, 10 lookups vs Array.find, 100 lookups

Created: 3 years ago by: Registered User

Jump to the latest result

Script Preparation code:

function getRandomElement(id) {
  return {
    id,
    a: Math.random(),
    b: Math.random(),
    c: Math.random(),
  }
}

function getArray(length) {
  const result = [];
  for (let i = 0; i < length; i++) {
    result.push(getRandomElement(i))
  }
  
  return result;
}

function arrayToMap(array) {
  return new Map(array.map(el => [el.id, el]));
}

function getRandomInt(max) {
  return Math.floor(Math.random() * max);
}

array_small = getArray(10000);
array_large = getArray(1000000);

map_small = arrayToMap(array_small);
map_large = arrayToMap(array_large);

Tests:

Array.find, 10 000 elements
const target = getRandomInt(9999); array_small.find(el => el.id === target);
Map.get, 10 000 elements
const target = getRandomInt(9999); map_small.get(target);
Array.find, 1 000 000 elements
const target = getRandomInt(999999); array_large.find(el => el.id === target);
Map.get, 1 000 000 elements
const target = getRandomInt(999999); map_large.get(target)
Array to Map + Map.get, 1 lookup
const map = arrayToMap(array_small); const target = getRandomInt(9999); map.get(target);
Array to Map + Map.get, 10 lookups
const map = arrayToMap(array_small); for (let i = 0; i < 10; i++) { const target = getRandomInt(9999); map.get(target); }
Array to Map + Map.get, 100 lookups
const map = arrayToMap(array_small); for (let i = 0; i < 100; i++) { const target = getRandomInt(9999); map.get(target); }
Array.find, 10 lookups
for (let i = 0; i < 10; i++) { const target = getRandomInt(9999); array_small.find(el => el.id === target) }
Array.find, 100 lookups
for (let i = 0; i < 100; i++) { const target = getRandomInt(9999); array_small.find(el => el.id === target) }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.find, 10 000 elements
Map.get, 10 000 elements
Array.find, 1 000 000 elements
Map.get, 1 000 000 elements
Array to Map + Map.get, 1 lookup
Array to Map + Map.get, 10 lookups
Array to Map + Map.get, 100 lookups
Array.find, 10 lookups
Array.find, 100 lookups

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 11 hours ago)

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:136.0) Gecko/20100101 Firefox/136.0

Browser/OS: Firefox 136 on Ubuntu

View result in a separate tab

Test name	Executions per second
Array.find, 10 000 elements	28812.3 Ops/sec
Map.get, 10 000 elements	207224048.0 Ops/sec
Array.find, 1 000 000 elements	243.4 Ops/sec
Map.get, 1 000 000 elements	207734224.0 Ops/sec
Array to Map + Map.get, 1 lookup	1308.4 Ops/sec
Array to Map + Map.get, 10 lookups	1224.6 Ops/sec
Array to Map + Map.get, 100 lookups	1302.4 Ops/sec
Array.find, 10 lookups	2213.5 Ops/sec
Array.find, 100 lookups	267.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided benchmark definition json represents a test case for comparing the performance of `Array.find` vs. `Map.get`. The test case has various configurations, including different array sizes and numbers of lookups.

**What is being tested?**

The test measures the performance of two approaches:

1.  **Array.find**: This method searches for an element in an array using a callback function.
2.  **Map.get**: This method retrieves a value from a Map data structure using its key.

**Performance metrics**

The benchmark reports various performance metrics, including:

*   `ExecutionsPerSecond`: The number of executions per second for each test configuration.
*   `TestName`: A unique identifier for each test case (e.g., "Map.get, 1 000 000 elements").
*   `DevicePlatform` and `OperatingSystem`: Information about the device platform and operating system used to run the benchmark.

**Comparison of Array.find and Map.get**

The results show that:

*   `Map.get` consistently performs better than `Array.find`, with higher execution rates for all test configurations.
*   The performance difference between `Map.get` and `Array.find` increases as the array size grows larger (e.g., 10,000 elements).
*   `Map.get` also outperforms `Array.find` when using a single lookup (1), while the performance gap narrows for multiple lookups (10 and 100).

**Implications**

These results suggest that `Map.get` is generally faster than `Array.find` due to its optimized internal implementation. This may be because Map's data structure is designed for efficient key-based access, whereas arrays are primarily suited for sequential iteration.

When choosing between these two methods, consider the following:

*   Use `Map.get` when working with key-value pairs or when you need fast lookups.
*   Use `Array.find` when you need to search for an element in a sequence of data (e.g., iterating over an array).

Keep in mind that this benchmark is specific to JavaScript and may not be representative of other programming languages.

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