Benchmark: Rest parameters vs array parameter v3

Script Preparation code:

const f1 = (...arr) => arr;
const f2 = (arr) => arr;

Tests:

Rest
const r1 = f1(0, 1, 2, 3, 4, 5);
Array
const r2 = f2([0, 1, 2, 3, 4, 5]);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Rest
Array

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser/OS: Chrome 134 on Windows

View result in a separate tab

Test name	Executions per second
Rest	243135168.0 Ops/sec
Array	246713680.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark you provided is designed to compare the performance of two different approaches for handling function parameters in JavaScript: using **rest parameters** versus using **array parameters**.

### Options Being Compared
1. **Rest Parameters (Test Name: "Rest")**:
   - **Function Definition**: `const f1 = (...arr) => arr;`
   - **Test Case**: `const r1 = f1(0, 1, 2, 3, 4, 5);`
   - **Description**: The rest parameter syntax (`...arr`) allows a function to accept an indefinite number of arguments as an array. It captures all remaining arguments into a single array, making it particularly useful when the number of inputs is not known in advance.

2. **Array Parameter (Test Name: "Array")**:
   - **Function Definition**: `const f2 = (arr) => arr;`
   - **Test Case**: `const r2 = f2([0, 1, 2, 3, 4, 5]);`
   - **Description**: This approach involves explicitly passing an array to the function. The function then processes this array directly. This can be more straightforward when the number of elements is known, as it avoids the additional syntactic overhead of rest parameters.

### Performance Results
Based on the benchmark results, the performance is measured in **executions per second** for each function under the same environment: Chrome 134 on a Windows Desktop.

- **Array**: 246,713,680.0 executions per second
- **Rest**: 243,135,168.0 executions per second

### Pros and Cons
**Rest Parameters**:
- **Pros**:
  - Flexibility to handle any number of arguments without manual array creation.
  - Cleaner syntax when calling the function.
- **Cons**:
  - Slightly less performant than the array parameter based on benchmark results.
  - Additional processing to gather all arguments into an array can add a trivial overhead.

**Array Parameters**:
- **Pros**:
  - Can be slightly more performant given the direct nature of handling an already defined array.
  - Simplicity when working with fixed-size arrays as input.
- **Cons**:
  - Less flexible for functions meant to handle unknown numbers of parameters; requires users to explicitly create and manage an array.
  - May result in clunkier syntax when calling the function with multiple arguments.

### Other Considerations
The choice between rest parameters and array parameters might depend on the context of the function being used:
- If a function consistently handles a variable number of input values, rest parameters might be preferable for their clarity and ease of use.
- On the other hand, if performance is a critical factor and the input size is known, explicitly using array parameters could optimize execution speed.

### Alternatives
Other common alternatives to manage multiple parameters or arrays include:
- **`arguments` Object**: Allows access to all arguments passed (not recommended for modern JavaScript due to its limitations).
- **Using Spread Syntax**: Particularly in conjunction with array methods like `.map()`, `.reduce()`, etc.
- **Higher-Order Functions**: Functions that return other functions, which can encapsulate data without requiring explicit array handling.

In conclusion, while rest parameters offer flexibility and modern syntax advantages, array parameters may yield better performance in specific contexts. Engineers should weigh these factors relative to their use cases when selecting the appropriate method for parameter handling in JavaScript.

Related benchmarks:

Rest parameters vs array parameter v3 (version: 1)

Comparing performance of: Rest vs Array

Created: one year ago by: Registered User

Jump to the latest result

Rest

Array

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):