Benchmark: Array merging - MeasureThat.net

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

var a = [
  { a: 'oh', b: 'my' },
  { c: 'goddess' },
  { a: 'anime'},
  { b: 'is', c: 'cool' }
];

Tests:

lodash assign from loop
var c = {}; _.forEach(a, (val, key) => { _.assign(c, {key: val}); });
object.assign from loop
var c = {}; _.forEach(a, (val, key) => { Object.assign(c, {key: val}); });
spread from loop
var c = {}; _.forEach(a, (val, key) => { c = {...c, key: val}; });
Manual forEach
var c = {}; _.forEach(a, (val, key) => { c[key] = val; });
lodash merge with spread
var c = {}; _.merge(c, ...a);
object assign with spread
var c = {}; Object.assign(c, ...a);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash assign from loop
object.assign from loop
spread from loop
Manual forEach
lodash merge with spread
object assign with spread

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

Let's break down what is tested in the provided JSON benchmark.

**Benchmark Definition**

The benchmark defines a JavaScript script that prepares an array `a` with some sample data and then merges it into an empty object `c` using different methods. The goal is to measure the performance of these merging methods.

**Options Compared**

There are four options compared:

1. **`.assign()` from Lodash**: This method assigns the values of one or more objects to a destination object.
2. **`Object.assign()`**: This method copies the properties of one or more source objects to a destination object.
3. **Spread operator (`...`) from loop**: This method uses the spread operator to create a new object with the merged properties.
4. **Manual `forEach` loop**: This method iterates over the array using a traditional `forEach` loop and assigns each value to an empty object.

**Pros and Cons of Each Approach**

1. **`.assign()` from Lodash**:
	* Pros: concise, efficient, and widely supported.
	* Cons: may have higher overhead due to the Lodash library.
2. **`Object.assign()`**:
	* Pros: widely supported, simple to use.
	* Cons: can be slower than `.assign()` for large datasets.
3. **Spread operator (`...`) from loop**:
	* Pros: concise, modern syntax, and potentially faster due to optimized implementations.
	* Cons: may not work in older browsers or environments.
4. **Manual `forEach` loop**:
	* Pros: lightweight, no external dependencies required.
	* Cons: verbose, error-prone, and slower compared to other methods.

**Library: Lodash**

Lodash is a popular JavaScript utility library that provides a wide range of functional programming helpers, including the `.assign()` method used in this benchmark. It can be included as a script tag or by using npm/yarn.

**Special JS Feature/Syntax: Spread Operator (`...`)**

The spread operator is a modern JavaScript feature introduced in ECMAScript 2015 (ES6). It allows you to expand an array or object into multiple arguments, making it concise and expressive. This benchmark uses the spread operator with the `Object.assign()` method.

**Other Considerations**

This benchmark highlights the importance of performance optimization in JavaScript development, especially when working with large datasets. The results suggest that the spread operator (`...`) from loop is one of the fastest methods, followed closely by `.assign()` from Lodash and then `Object.assign()`. However, the best approach depends on the specific use case, available dependencies, and desired trade-offs between conciseness, readability, and performance.

If you're interested in exploring alternative approaches, here are some additional options:

* **`reduce()` method**: This method can be used to merge objects by accumulating values in a callback function.
* **`forEach()` with object creation**: Similar to the manual `forEach` loop approach, but uses object literals instead of empty objects.
* **Native array methods**: Some browsers and environments have native array methods like `reduce()`, `map()`, or `filter()` that can be used for merging.

Keep in mind that these alternatives may have different performance characteristics or require additional dependencies.

Related benchmarks:

Array merging (version: 2)

Comparing performance of: lodash assign from loop vs object.assign from loop vs spread from loop vs Manual forEach vs lodash merge with spread vs object assign with spread

Created: 5 years ago by: Registered User

Jump to the latest result

lodash assign from loop

object.assign from loop

spread from loop

Manual forEach

lodash merge with spread

object assign with spread

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):