Benchmark: bench concat spread jeff2

Tests:

concat
let a = 1;
spread
let i, x; let a = (new Array(1e3)).fill(99); let b = (new Array(1e3)).fill(99); let c = (new Array(1e3)).fill(99); let d = (new Array(1e3)).fill(99); for(i = 0; i < 1e2; i++) x = [1,2,3, ...a, ...b, ...c, ...d]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat
spread

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is an essential task for any developer, and MeasuringThat.net provides a great platform for it.

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

**Benchmark Definition**

The benchmark definition represents a simple arithmetic expression: `let a = 1;`. This is just a placeholder to allow users to create their own benchmarks. The actual benchmark script will be executed, and its performance will be measured.

**Individual Test Cases**

There are two test cases:

1. **"concat"**: This test case measures the performance of concatenating arrays using the spread operator (`...`). In the benchmark definition, an array `a` is filled with 999 values. The test code creates four more arrays `b`, `c`, and `d`, each also filled with 999 values. The loop iterates 10,000 times, and in each iteration, it adds all four arrays to a new array `x`. The spread operator (`...`) is used to concatenate the arrays.
2. **"spread"**: This test case measures the performance of using the spread operator (`...`) without any additional context. In this benchmark definition, an array `x` is initialized with the value `[1, 2, 3]`, and then four more arrays `a`, `b`, `c`, and `d` are filled with 999 values. The loop iterates 10,000 times, and in each iteration, it uses the spread operator to concatenate all four arrays to the array `x`.

**Performance Comparison**

The benchmark measures the execution time of both test cases on a Chrome 79 browser.

**Pros and Cons of Spread Operator Approach**

Using the spread operator (`...`) can provide several benefits:

*   **Concise syntax**: The spread operator allows for more concise code and easier data manipulation.
*   **Efficient memory allocation**: When used with arrays, it avoids creating intermediate arrays and directly appends elements to the destination array.

However, there are also some potential drawbacks:

*   **Potential performance overhead**: In certain scenarios, using the spread operator can introduce additional overhead due to its syntax and behavior.
*   **Unpredictability in older browsers or engines**: The spread operator might not be supported by older browsers or JavaScript engines, which could lead to unexpected results.

**Library Usage**

Neither of the test cases uses any external libraries. The benchmark is self-contained and relies on standard JavaScript features.

**Special JS Features or Syntax**

There are no special JS features or syntax used in these test cases. The focus is solely on measuring the performance of the spread operator (`...`) in different scenarios.

**Alternatives**

If you want to create your own benchmarks using MeasuringThat.net, here's a brief guide:

1.  Create a new benchmark by going to the MeasuringThat.net website and clicking "Create Benchmark".
2.  Fill in the required information, such as the benchmark name, description, script preparation code, and HTML preparation code.
3.  Define your test cases using the JSON format provided above.

Some additional tips:

*   Make sure to use meaningful names for your variables and functions to make it easier to understand your benchmarks.
*   Consider adding comments to your code to explain its purpose and behavior.
*   Be mindful of potential performance overhead or browser compatibility issues when designing your benchmarks.

I hope this explanation helps you understand the provided benchmark and provides a solid foundation for creating your own JavaScript performance benchmarks.

Related benchmarks:

bench concat spread jeff2 (version: 0)

Comparing performance of: concat vs spread

Created: 5 years ago by: Guest

Jump to the latest result

concat

spread

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):