Benchmark: object spread vs object index vs map set

Tests:

object update with spread operator
let obj = {} for (let i = 0; i < 1000; i++) { obj = {...obj, [i]: (i || 0) + 1} }
object update with indexing
const obj = {} for (let i = 0; i < 1000; i++) { obj[i] = (obj[i] || 0) + 1 }
map update
const map = new Map() for (let i = 0; i < 1000; i++) { map.set(i, (map.get(i) || 0) + 1) }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
object update with spread operator
object update with indexing
map update

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.97 Safari/537.36

Browser/OS: Chrome 96 on Linux

View result in a separate tab

Test name	Executions per second
object update with spread operator	2739.1 Ops/sec
object update with indexing	53870.3 Ops/sec
map update	24568.5 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided benchmark measures the performance of three different approaches to update an object in JavaScript: using the spread operator (`object spread`), indexing (`object index`), and using a `Map` data structure (`map set`). The benchmark aims to compare the execution speed of these approaches.

**Options Compared**

1. **Object Spread**: This approach uses the spread operator (`...`) to update an object by spreading its current properties into a new object, and then overwriting the existing properties with the new ones.
2. **Object Indexing**: This approach uses indexing (`obj[i] = ...`) to update an object's property at a specific key (`i`).
3. **Map Set**: This approach uses a `Map` data structure to store key-value pairs, and updates the value associated with a given key.

**Pros and Cons of Each Approach**

1. **Object Spread**:
	* Pros: concise syntax, easy to read and write.
	* Cons: might incur additional overhead due to object cloning.
2. **Object Indexing**:
	* Pros: lightweight, fast access to properties.
	* Cons: can be less readable, especially for complex objects.
3. **Map Set**:
	* Pros: efficient updates with O(1) average time complexity.
	* Cons: might require additional library or polyfill due to Map's non-standard behavior in older browsers.

**Library and Syntax Used**

In the provided benchmark, no specific libraries are used beyond the standard JavaScript features. However, it is worth noting that some implementations of `Map` may rely on non-standard browser features, such as `Object.create()` or `Array.prototype.indexOf()`, to provide efficient updates.

**Special JS Feature/Syntax**

The spread operator (`...`) is a relatively recent addition to JavaScript, introduced in ECMAScript 2018 (ES10). It allows creating new objects by spreading an existing object's properties into a new object. The indexing approach (`obj[i] = ...`) uses the `Array.prototype.length` property to access array-like objects.

**Other Alternatives**

If you need to update an object, other alternatives to these approaches include:

1. Using `Object.assign()`: A more traditional way of updating an object by copying properties from another object.
2. Using a library like Lodash's `assignIn()` or `merge()`: Provides more features and flexibility for updating objects.
3. Using a functional programming approach with `currying` or `memoization`: Can lead to more efficient updates, especially in complex scenarios.

For Map-based data structures, consider using libraries like Lodash's `mapSet()` or `mapDelete()`, which provide additional functionality beyond the basic `Map` API.

When choosing an approach, consider factors such as:

* Performance requirements
* Code readability and maintainability
* Browser compatibility (if required)
* Additional library dependencies

Ultimately, the best approach depends on your specific use case and personal preference.

Related benchmarks:

object spread vs object index vs map set (version: 0)

Comparing performance of: object update with spread operator vs object update with indexing vs map update

Created: 2 years ago by: Guest

Jump to the latest result

object update with spread operator

object update with indexing

map update

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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