Benchmark: JavaScript reduce assign vs spread vs forEach baseline

Tests:

Object Assign
const data = [{id: 1, category: "frontend", title: "All About That Sass"}, {id: 2, category: "backend", title: "Beam me up, Scotty: Apache Beam tips"}, {id: 3, category: "frontend", title: "Sanitizing HTML: Going antibactirial on XSS attacks"}, {id: 4, category: "frontend", title: "Doing something Odd"}, {id: 5, category: "frontend", title: "How to rebuild the moon?"}]; const reduced = data.reduce((acc, item) => { acc[item.id] = item; return acc; }, {});
Object Spread
const data = [{id: 1, category: "frontend", title: "All About That Sass"}, {id: 2, category: "backend", title: "Beam me up, Scotty: Apache Beam tips"}, {id: 3, category: "frontend", title: "Sanitizing HTML: Going antibactirial on XSS attacks"}, {id: 4, category: "frontend", title: "Doing something Odd"}, {id: 5, category: "frontend", title: "How to rebuild the moon?"}]; const reduced = data.reduce((acc, item) => ({ ...acc, [item.id]: item }), {});
Object Assign Library
const data = [{id: 1, category: "frontend", title: "All About That Sass"}, {id: 2, category: "backend", title: "Beam me up, Scotty: Apache Beam tips"}, {id: 3, category: "frontend", title: "Sanitizing HTML: Going antibactirial on XSS attacks"}, {id: 4, category: "frontend", title: "Doing something Odd"}, {id: 5, category: "frontend", title: "How to rebuild the moon?"}]; const reduced = data.reduce((acc, item) => Object.assign(acc, {[item.id]: item}), {});
forEach comparison
const data = [{id: 1, category: "frontend", title: "All About That Sass"}, {id: 2, category: "backend", title: "Beam me up, Scotty: Apache Beam tips"}, {id: 3, category: "frontend", title: "Sanitizing HTML: Going antibactirial on XSS attacks"}, {id: 4, category: "frontend", title: "Doing something Odd"}, {id: 5, category: "frontend", title: "How to rebuild the moon?"}]; const reduced = {}; data.forEach((item) => { reduced[item.id] = item });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object Assign
Object Spread
Object Assign Library
forEach comparison

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's dive into the benchmark and explain what's being tested.

The benchmark is comparing three ways to reduce an array of objects to an object with only the desired properties:

1. **Array Reduction using Object Assign** (`Object.assign()`)
2. **Array Reduction using Object Spread** (`{ ...acc, [item.id]: item }`)
3. **Array Reduction using a ForEach loop** (not using any built-in array or object methods)

**Option 1: Array Reduction using Object Assign**

This approach uses the `Object.assign()` method to merge two objects. In this case, it's used to create a new object with the desired properties from the original array.

Pros:

* Simple and straightforward
* Fast and efficient

Cons:

* Requires the use of `Object.assign()`, which can be slower than other approaches for large arrays.
* Can lead to unexpected behavior if not used carefully (e.g., if the accumulator is not an object).

**Option 2: Array Reduction using Object Spread**

This approach uses the spread operator (`{ ...acc, [item.id]: item }`) to create a new object with the desired properties from the original array.

Pros:

* Fast and efficient
* Does not require the use of `Object.assign()`
* Easy to read and understand

Cons:
* May be slower than Option 1 for very large arrays (due to the creation of a new object).
* Can lead to unexpected behavior if not used carefully (e.g., if the accumulator is not an object).

**Option 3: Array Reduction using a ForEach loop**

This approach uses a traditional `for` loop and array indexing to iterate over the array and create a new object with the desired properties.

Pros:

* Simple and straightforward
* Does not require any built-in array or object methods

Cons:
* Can be slower than Options 1 and 2 (especially for large arrays)
* May lead to more errors due to manual indexing and looping.

Now, let's talk about the libraries mentioned in the benchmark. There is none explicitly mentioned. However, `Object.assign()` is a built-in JavaScript method that can be considered a library of sorts.

The special JS feature used here is not explicitly mentioned. The spread operator (`{ ...acc, [item.id]: item }`) was introduced in ES6 (ECMAScript 2015) and has become a standard feature in modern JavaScript.

Finally, there are several alternatives to these approaches:

* Using `Array.prototype.reduce()` with a callback function: This is another built-in JavaScript method that can be used for array reduction.
* Using `lodash` library's `pick()` method: If you're using the Lodash library, you can use its `pick()` method to achieve similar results.
* Manual implementation without using any built-in methods: You could implement a custom solution using manual looping and indexing, but this would likely be slower and more error-prone.

I hope this explanation helps!

Related benchmarks:

JavaScript reduce assign vs spread vs forEach baseline (version: 0)

Comparing performance of: Object Assign vs Object Spread vs Object Assign Library vs forEach comparison

Created: 4 years ago by: Guest

Jump to the latest result

Object Assign

Object Spread

Object Assign Library

forEach comparison

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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