Benchmark: Array descruct via [], {} and direct by index

Script Preparation code:

const arr = ["first", "second", "third"]

Tests:

[] descruct
/*When writing async/deferred tests, use `deferred.resolve()` to mark test as done*/ const [first, second, third] = arr;
{} destruct
const {0:first, 1:second, 2:third} = arr;
direct
const first = arr[0]; const second = arr[1]; const third = arr[2];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
[] descruct
{} destruct
direct

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
[] descruct	146903232.0 Ops/sec
{} destruct	144011424.0 Ops/sec
direct	125819232.0 Ops/sec

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

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON focuses on testing different methods of destructuring and accessing elements from an array in JavaScript.

### Options Compared

1. **Array Destructuring using Square Brackets (`[]`)**:
   - **Test Name**: `[] destruct`
   - **Benchmark Definition**: 
     ```javascript
     const [first, second, third] = arr;
     ```
   - **Description**: This syntax allows extracting values from an array into distinct variables in a concise and readable manner.

2. **Destructuring with Object Notation (`{}`)**:
   - **Test Name**: `{} destruct`
   - **Benchmark Definition**:
     ```javascript
     const {0:first, 1:second, 2:third} = arr;
     ```
   - **Description**: This approach uses object destructuring, where the array's indices are mapped to variable names. However, it is less commonly used for arrays and can introduce additional complexity.

3. **Direct Index Access**:
   - **Test Name**: `direct`
   - **Benchmark Definition**:
     ```javascript
     const first = arr[0];
     const second = arr[1];
     const third = arr[2];
     ```
   - **Description**: This method directly accesses array elements by their indices and assigns them to variables. It is the most straightforward approach but can be less elegant than destructuring.

### Performance Results

The benchmark results show the average number of executions per second for each method tested in Chrome 131 on macOS:

- **[] destruct**: 146,903,232 executions per second
- **{} destruct**: 144,011,424 executions per second
- **direct**: 125,819,232 executions per second

### Pros and Cons of Each Approach

1. **Array Destructuring (`[]`)**:
   - **Pros**:
     - Concise and clear, improves readability.
     - Less code and easier to manage when dealing with multiple variables.
   - **Cons**:
     - None significant; generally preferred for extracting multiple values.

2. **Object Notation (`{}`)**:
   - **Pros**:
     - Theoretically allows named variables at assignment.
   - **Cons**:
     - Less conventional for arrays; can create confusion.
     - Slightly lower performance compared to array destructuring as observed in the results.

3. **Direct Index Access**:
   - **Pros**:
     - Very straightforward and clear, especially for those new to JavaScript.
     - Explicit indexing makes it clear what is being accessed.
   - **Cons**:
     - More verbose, leading to potential repetitive code.
     - Prone to errors if the array size changes or if you mistakenly reference wrong indices.

### Other Considerations

- **Readability vs. Performance**: While performance may slightly favor array destructuring, in most real-world applications, both readability and maintainability are critical. Destructuring, in many cases, strikes a good balance between performance and syntax clarity.
  
- **Alternative Approaches**: Aside from the methods discussed, other alternatives to access array elements include using higher-order functions like `map()`, `forEach()`, or the spread operator in certain contexts, although these approaches typically don't provide the same direct assignment functionality as destructuring or index access.

- **Use Cases**: In practice, developers often prefer destructuring for its readability, especially when dealing with larger arrays or objects, but direct index access can be more efficient for accessing individual elements when performance is paramount.

Ultimately, the choice between these methods can depend on the specific use case, codebase conventions, and team preferences.

Related benchmarks:

Array descruct via [], {} and direct by index (version: 1)

Comparing performance of: [] descruct vs {} destruct vs direct

Created: one year ago by: Guest

Jump to the latest result

[] descruct

{} destruct

direct

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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