Benchmark: Spread vs Object assign to update

Tests:

Spread
let firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } firstObject = { ...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

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36

Browser/OS: Chrome 83 on Windows

View result in a separate tab

Test name	Executions per second
Spread	18154406.0 Ops/sec
Object.assign	3504240.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested.

**Benchmark Overview**

The benchmark measures the performance difference between using the spread operator (`...`) to update an object versus using `Object.assign()` for updating objects in JavaScript.

**Options Compared**

Two options are compared:

1. **Spread Operator (`...`)**: This operator allows you to create a new object by copying properties from an existing object.
2. **Object.assign()**: This method copies all enumerable own properties of source objects to a target object.

**Pros and Cons**

* **Spread Operator (`...`)**:
	+ Pros:
		- More concise and readable code.
		- No need to create a new object or use an intermediate variable.
	+ Cons:
		- May have performance overhead due to the creation of a new object.
		- Limited support in older browsers (Internet Explorer 11 and earlier).
* **Object.assign()**:
	+ Pros:
		- Wide browser support, including older versions.
		- Allows for more control over the assignment process (e.g., assigning only specific properties).
	+ Cons:
		- Less concise code compared to the spread operator.
		- May require intermediate variables or more complex logic.

**Library and Special JavaScript Features**

In this benchmark, there is no explicit library mentioned. However, some general assumptions can be made:

* The `...` spread operator was introduced in ECMAScript 2015 (ES6) and is widely supported across modern browsers.
* `Object.assign()` has been part of the JavaScript standard since ECMAScript 2009.

**Other Considerations**

When deciding between the spread operator and `Object.assign()`, consider the following factors:

* Code readability: If you prioritize conciseness, the spread operator might be a better choice. If you prioritize clarity, `Object.assign()` might be more suitable.
* Performance: For large objects or performance-critical code, using an intermediate variable with `Object.assign()` might provide better results.

**Other Alternatives**

For updating objects in JavaScript, other methods exist:

1. **Destructuring assignment**: Similar to the spread operator but used for assigning values from an array or object.
2. **JSON merge libraries**: Libraries like JSONMerge or Lodash's assign() function can help with merging objects while handling edge cases and null/undefined values.
3. **Other methods**: Some developers might use other approaches, such as using a utility library to create a new object or assigning properties one by one.

Keep in mind that the spread operator has become a widely accepted and efficient method for updating objects in modern JavaScript development.

Related benchmarks:

Spread vs Object assign to update (version: 0)

Comparing performance of: Spread vs Object.assign

Created: 4 years ago by: Guest

Jump to the latest result

Spread

Object.assign

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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