Benchmark: Spread vs Object.assign vs Object.keys and reduce

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign(firstObject, secondObject);
Not merging
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.keys(firstObject).reduce((acc, key) => { acc[key] = firstObject[key] return acc }, {})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the spread operator
Using Object.assign
Not merging

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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**Benchmark Overview**

The provided JSON represents a JavaScript benchmark test case at MeasureThat.net. The test compares the performance of three different methods to merge two objects: using the spread operator (`...`), `Object.assign()`, and a custom implementation without merging (`Not merging`).

**Options Compared**

1. **Using the spread operator (`...`)**:
	* This method uses the rest operator (`...`) to merge the properties of two objects into a new object.
	* Pros: concise, readable, and efficient for simple cases.
	* Cons: may not work correctly with non-plain object types (e.g., arrays), and its performance can vary depending on the browser's engine.
2. **`Object.assign()`**:
	* This method uses the `assign()` function to merge the properties of two objects into a new object.
	* Pros: widely supported, including in older browsers, and works with non-plain object types.
	* Cons: can be less efficient than using the spread operator for simple cases, and its performance may vary depending on the browser's engine.
3. **`Not merging`**:
	* This method creates a new object by concatenating the properties of two objects using `reduce()`.
	* Pros: allows for more control over the merge process, but can be less efficient than other methods for simple cases.
	* Cons: may require more code and is not as concise as other methods.

**Library**

None of the benchmark test cases use any external libraries. The tests rely solely on native JavaScript features and built-in functions like `Object.assign()`.

**Special JS Feature/Syntax**

The test uses the rest operator (`...`) introduced in ECMAScript 2018, which allows for more concise object merging. Additionally, it uses the `reduce()` function, which is a built-in JavaScript method that iterates over an array or other iterable and applies a callback function to each element.

**Other Alternatives**

If you want to explore alternative methods for merging objects in JavaScript, consider using:

1. **Lodash's `merge()` function**: A popular utility library that provides a robust implementation of object merging.
2. **Underscore.js's `_merge()` function**: Another utility library that offers an efficient and flexible way to merge objects.
3. **A custom implementation using loops or recursion**: While not as concise or readable as the above methods, you can write your own object merging function using JavaScript's built-in features.

Keep in mind that while these alternatives may offer more control or flexibility, they might also come with a performance overhead or require more code to implement.

Related benchmarks:

Spread vs Object.assign vs Object.keys and reduce (version: 0)

Comparing performance of: Using the spread operator vs Using Object.assign vs Not merging

Created: 6 years ago by: Guest

Jump to the latest result

Using the spread operator

Using Object.assign

Not merging

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):