Benchmark: Object.assign vs spread operatordd

Tests:

Object.assign
var params = { b:"hello", c: true, d:7 }; var other = Object.assign({ a: 2 }, params);
spread operator
var params = { b:"hello", c: true, d:7 }; var other = { a: 2, ...params };

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
spread operator

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 break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark compares two ways of merging objects in JavaScript: `Object.assign()` and the spread operator (`...`).

**Test Cases**

There are two test cases:

1. **`Object.assign()`**: This test case uses the `Object.assign()` method to merge an object with a new object containing some properties.
```javascript
var params = { b:"hello", c: true, d:7 };
var other = Object.assign({ a: 2 }, params);
```
The idea is to create a new object by copying the `a` property from the first object and merging the rest of the properties from the second object.

Pros:

* Simple and straightforward
* Widely supported in older browsers

Cons:

* Can lead to shallow copies, which might not be what you want (e.g., arrays are copied as references)
* Can be slower due to the need for a loop or array method

2. **Spread Operator (`...`)**: This test case uses the spread operator to merge an object with a new object containing some properties.
```javascript
var params = { b:"hello", c: true, d:7 };
var other = { a: 2, ...params };
```
The idea is to create a new object by copying all properties from the first object and merging them into the second object.

Pros:

* More concise and readable
* Creates shallow copies of arrays as required

Cons:

* Might not work in older browsers that don't support the spread operator
* Can be slower due to the need for additional checks or array method calls

**Library Used**

None, this is a pure JavaScript benchmark.

**Special JS Features/Syntax**

The spread operator (`...`) is a relatively new feature introduced in ECMAScript 2018 (ES2018). It's supported in modern browsers and Node.js versions, but not in older browsers or environments that don't support ES2018.

**Other Alternatives**

If you're working with older browsers or environments that don't support the spread operator, you can use other methods to merge objects, such as:

* `Object.assign()`: As mentioned earlier
* `for...in` loop: Iterate over the properties of one object and add them to another using a `for...in` loop.
* `Array.prototype.concat()`: Create an array of property values from each object and then use `Array.prototype.concat()` to merge them into a new array.

Keep in mind that these alternatives might not be as concise or readable as the spread operator, but they can still get the job done.

Related benchmarks:

Object.assign vs spread operatordd (version: 0)

Comparing performance of: Object.assign vs spread operator

Created: 6 years ago by: Guest

Jump to the latest result

Object.assign

spread operator

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):