Benchmark: Spread vs Object assign if we want a new object to be created

Tests:

spread
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign({},firstObject, secondObject);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
Object.assign

Fastest: N/A

Slowest: N/A

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

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Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

The provided benchmark measures the performance difference between two approaches: using the spread operator (`...`) to merge objects and using `Object.assign()` to merge objects.

**Spread Operator (...)
The spread operator is a feature introduced in ECMAScript 2015 (ES6). It allows you to expand an object's properties into another object. In this benchmark, it's used to create a new object by merging two existing objects: `firstObject` and `secondObject`. The syntax `const finalObject = { ...firstObject, ...secondObject }` is used to achieve this.

**Pros of using the spread operator:**

1. **Readability**: The code is more concise and easier to read.
2. **Efficiency**: It creates a new object with the merged properties, which can be faster than modifying an existing object.
3. **Flexibility**: It allows you to merge objects in a more declarative way.

**Cons of using the spread operator:**

1. **Browser support**: Although widely supported, some older browsers might not have it enabled by default.
2. **Performance**: In some cases, the spread operator can be slower than `Object.assign()` due to additional overhead.

**Object.assign()**
`Object.assign()` is a method of the `Object` prototype that allows you to copy properties from one or more source objects to a target object. In this benchmark, it's used to merge the same two objects: `firstObject` and `secondObject`. The syntax `const finalObject = Object.assign({}, firstObject, secondObject)` is used.

**Pros of using `Object.assign()`:**

1. **Wide browser support**: `Object.assign()` has been supported by most browsers for a long time.
2. **Performance**: It can be faster than the spread operator in some cases due to less overhead.

**Cons of using `Object.assign()`:**

1. **Verbosity**: The code is more verbose and harder to read.
2. **Mutability**: It modifies the original objects, which might not be desirable in all situations.

Other alternatives that could have been used in this benchmark are:

* Using the `Object.create()` method to create a new object and then using the spread operator or `Object.assign()` to merge properties into it.
* Using a library like Lodash's `merge` function, which provides a more flexible way of merging objects.

Keep in mind that the choice of approach depends on the specific use case, personal preference, and performance requirements.

Related benchmarks:

Spread vs Object assign if we want a new object to be created (version: 0)

Comparing performance of: spread vs Object.assign

Created: 6 years ago by: Guest

Jump to the latest result

spread

Object.assign

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):