Benchmark: Dict vs. Map vs. Array

Script Preparation code:

var dict= {}
for (var i=0; i<50000; i++) {
  dict['abc_'+i] = i;
}

var map= new Map()
for (var i=0; i<50000; i++) {
  map.set('abc_'+i, i);
}

var arr = []
for (var i=0; i<50000; i++) {
  arr.push(i);
}

Tests:

Dictionary
let c = 0 for (i=2000; i<10000; i+=115) { c += dict['abc_'+i]}
Array
let c = 0 for (i=2000; i<10000; i+=115) { c += arr[i]}
Map
let c = 0 for (i=2000; i<10000; i+=115) { c += map.get('abc_'+i)}

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Chrome 11 runs

Array

411K/s

Dictionary

216K/s

Map

133K/s

Fastest: Array (3.1x faster)

View exact numbers

✓ Array: 411,158 ops/sec
• Dictionary: 216,426 ops/sec
• Map: 132,794 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
Dictionary
Array
Map

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36

Browser/OS: Chrome 143 on Windows

View result in a separate tab

Array

408K/s

Dictionary

251K/s

Map

131K/s

View exact numbers

Test name	Executions per second
✓ Array	408,424 Ops/sec
Dictionary	251,113 Ops/sec
Map	130,588 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 provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark is designed to compare the performance of three data structures: an array, a Map (similar to JavaScript's Object), and a dictionary (JavaScript's Object). The test cases are prepared using the provided Script Preparation Code.

**Script Preparation Code**

The script prepares large arrays, dictionaries, and Maps with 50,000 elements each. It then defines a function `c` that iterates over the arrays, dictionaries, or Maps to calculate their sum using various methods:

* Array: accessing elements by index (`arr[i]`)
* Dictionary: accessing elements by key (`dict['abc_'+i]`)
* Map: accessing elements using the `get()` method (`map.get('abc_'+i)`)

**Options Compared**

The benchmark compares the following options:

1. **Dictionary**: Accessing elements by key using `dict['abc_'+i]`
2. **Array**: Accessing elements by index using `arr[i]`
3. **Map**: Accessing elements using the `get()` method with a string key (`map.get('abc_'+i)`)

**Pros and Cons of Each Approach**

1. **Dictionary**:
	* Pros: Fast lookups, since keys are hashed.
	* Cons: Slower iteration due to slower indexing on objects.
2. **Array**:
	* Pros: Simple, fast indexing.
	* Cons: May lead to slow iterations if the array is very large.
3. **Map**:
	* Pros: Efficient for large datasets with unique keys, as it uses hashing.
	* Cons: May have additional overhead due to the `get()` method and the need for a key string.

**Library and Purpose**

The script uses the following libraries:

1. None explicitly mentioned; however, JavaScript's built-in objects (Array, Object, Map) are used.

**Special JS Feature or Syntax**

None mentioned in this specific benchmark, as it only involves basic iteration and data access methods.

**Other Alternatives**

Alternatives to this benchmark could include:

* Comparing other data structures like Sets or Linked Lists.
* Using different iteration methods, such as using `forEach()` or `reduce()`.
* Adding more complex operations, such as sorting or inserting elements.

These alternatives would help further evaluate the performance characteristics of each data structure in various scenarios.

Dict vs. Map vs. Array (version: 0)

Large dictionary - how worse is it from array with direct reference? And how does Map perform?

Comparing performance of: `Dictionary vs Array vs Map`

Created: 7 years ago by: Registered User

Go to the latest result

Dictionary

Array

Map

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Chrome 11 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Dict vs. Map vs. Array (version: 0)

Large dictionary - how worse is it from array with direct reference? And how does Map perform?

Comparing performance of: Dictionary vs Array vs Map

Created: 7 years ago by: Registered User

Go to the latest result

Dictionary

Array

Map

Historical Performance Data aggregated from 11 community runs

Desktop Results:

Chrome 11 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: `Dictionary vs Array vs Map`