Benchmark: map vs object 2 2 2 2

Tests:

map
var map = new Map() var key1 = String(Math.random()) var key2 = String(Math.random()) map.set(key1, key1) map.set(key2, key2) var times = 8 while (times--) { map.get(Math.random() > 0.5 ? key1 : key2) }
object
var obj = {} var key1 = String(Math.random()) var key2 = String(Math.random()) obj[key1] = key1 obj[key2] = key2 var times = 8 while (times--) { obj[Math.random() > 0.5 ? key1 : key2] }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map
object

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_1_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.1.2 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 17 on iOS 17.1.2

View result in a separate tab

Test name	Executions per second
map	1113292.6 Ops/sec
object	777810.6 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 definition and test cases.

**Benchmark Definition**
The benchmark definition is a JSON object that contains two identical test cases: `map` and `object`. The purpose of this benchmark is to compare the performance of using a `Map` data structure versus an object literal (`{}`) to store key-value pairs in JavaScript.

**Script Preparation Code**
There is no script preparation code provided, which means that the test cases are designed to be executed directly in the browser or Node.js environment without any additional setup.

**Html Preparation Code**
There is also no html preparation code provided, which suggests that the benchmark only runs JavaScript tests and does not involve rendering HTML content.

**Individual Test Cases**

### Map

The `map` test case creates a new instance of the `Map` class and sets two key-value pairs: `key1` and `key2`, both with the same value as their keys. The test then enters a loop that executes the following code 8 times:

* Retrieves a random key from either `key1` or `key2` using the `get()` method.
* The retrieval is done randomly, depending on whether `Math.random() > 0.5`.

### Object

The `object` test case creates an empty object literal and sets two key-value pairs: `key1` and `key2`, both with the same value as their keys. The test then enters a loop that executes the following code 8 times:

* Retrieves a random key from either `key1` or `key2` using bracket notation (`obj[key]`).
* The retrieval is done randomly, depending on whether `Math.random() > 0.5`.

**Pros and Cons**

The main difference between these two approaches is how the keys are looked up:

* In the `map` test case, the keys are accessed using the `get()` method, which returns a value or throws an error if the key is not found.
* In the `object` test case, the keys are accessed using bracket notation (`obj[key]`), which directly returns the corresponding value.

**Pros of using Map:**

* Faster lookup times since `Map` uses a hash table data structure under the hood.
* More explicit control over whether to return a value or throw an error when a key is not found.

**Cons of using Map:**

* May require additional type checking or handling for cases where the returned value needs to be treated as a specific type.

**Pros of using Object Literal:**

* Familiar syntax and semantics for most developers.
* No additional overhead or configuration required.

**Cons of using Object Literal:**

* Slower lookup times due to linear search through the object's property list.
* May lead to unexpected behavior if not handled carefully (e.g., null, undefined keys).

**Library and Purpose**

The `Map` class is a built-in JavaScript data structure introduced in ECMAScript 2015. Its primary purpose is to provide fast and efficient key-value pair storage, allowing for easy iteration and lookup of values.

**Special JS Feature or Syntax**
There are no special JavaScript features or syntax used in these test cases beyond the use of `Map` and object literals.

Related benchmarks:

map vs object 2 2 2 2 (version: 0)

Comparing performance of: map vs object

Created: 2 years ago by: Registered User

Jump to the latest result

map

object

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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