Benchmark: Object.assign vs spread operator SM

Tests:

Object.assign
const foo = { foo: 1, bar: true, baz:'baz' }; const result = Object.assign({ foo: 2, bar: false }, foo );
Spread
const foo = { foo: 1, bar: true, baz:'baz' }; const result = { foo: 2, bar: false, ...foo };

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
Spread

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Linux; Android 8.1.0; SM-J327W) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.90 Mobile Safari/537.36

Browser/OS: Chrome Mobile 73 on Android 8.1.0

View result in a separate tab

Test name	Executions per second
Object.assign	418188.5 Ops/sec
Spread	344695.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its options.

**Benchmark Overview**

The MeasureThat.net website allows users to create and run JavaScript microbenchmarks. The provided benchmark is called "Object.assign vs spread operator SM". This benchmark compares the performance of two approaches: `Object.assign` and the spread operator (`...`).

**Options Compared**

The benchmark tests the following options:

1. **Object.assign**: This method creates a new object by copying properties from an existing object.
2. **Spread Operator (`...`)**: This syntax creates a new object with the given key-value pairs, using the spread operator to merge objects.

**Pros and Cons of Each Approach**

*   **Object.assign**:
    *   Pros:
        *   Widely supported in most browsers
        *   Well-documented and widely used in the JavaScript community
    *   Cons:
        *   Can be slower than the spread operator due to the overhead of function calls
        *   May not work correctly for complex object structures or null/undefined values
*   **Spread Operator (`...`)**:
    *   Pros:
        *   Generally faster than `Object.assign`
        *   More concise and readable code
    *   Cons:
        *   Less widely supported in older browsers (e.g., Internet Explorer)
        *   May not work correctly for complex object structures or null/undefined values

**Library Used**

In the benchmark, no libraries are explicitly mentioned. However, `Object.assign` is a built-in JavaScript method.

**Special JS Feature/Syntax**

The spread operator (`...`) is a relatively new feature introduced in ECMAScript 2018 (ES2018). It allows for more concise and readable object creation.

**Other Considerations**

When deciding between these two approaches, consider the following:

*   If you're targeting older browsers that don't support the spread operator, `Object.assign` might be a better choice.
*   If performance is critical, the spread operator might be a better option due to its generally faster execution time.
*   In terms of readability and maintainability, the spread operator can result in more concise code.

**Alternatives**

Other alternatives for merging objects or creating new objects include:

*   **Object.create()**: This method creates a new object with the given prototype.
*   **Array.prototype.reduce()**: This method applies a function to each element of an array and returns a new array.
*   **lodash's _.merge()` method**: This method merges two or more objects into one.

Keep in mind that these alternatives might have different performance characteristics, readability, and maintainability compared to `Object.assign` and the spread operator.

Related benchmarks:

Object.assign vs spread operator SM (version: 0)

Comparing performance of: Object.assign vs Spread

Created: 5 years ago by: Guest

Jump to the latest result

Object.assign

Spread

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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