Benchmark: padStart vs splice

Tests:

padStart
let x = 5; let res = ("" + x).padStart(2, "0")
splice
let x = 5; let res = ("0" + x).slice(-2)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
padStart
splice

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Windows

View result in a separate tab

Test name	Executions per second
padStart	40784648.0 Ops/sec
splice	116395824.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested on the provided JSON and explain the different approaches compared.

**Benchmark Overview**

The benchmark measures the speed difference between two JavaScript methods: `padStart` and `splice`. Specifically, it tests how fast each method can be used to pad a string with leading zeros.

**Methods Compared**

1. **padStart**: This method pads a string with leading characters (in this case, zeros) until it reaches a specified length.
2. **splice**: Although not directly related to padding strings, `splice` is often used as a workaround for achieving similar results. In the benchmark, it's used by taking a substring of the original string (`slice(-2)`).

**Pros and Cons**

*   **padStart**:
    *   Pros: More idiomatic JavaScript way to pad strings.
    *   Cons: May not be supported in older browsers or environments that don't have modern JavaScript implementations. Some might argue that it's a bit verbose for such a simple operation.
*   **splice** (used as a workaround):
    *   Pros: Works in more browsers and environments due to its native support.
    *   Cons: Not the intended method for padding strings, which can lead to slower performance.

The choice of method ultimately depends on your specific use case, target audience, and compatibility requirements. If you're targeting modern browsers and don't mind using a slightly more verbose approach, `padStart` is generally preferred.

**Library/Features Used**

*   No external libraries are mentioned in the benchmark definition or individual test cases.
*   **Special JS feature or syntax**: The use of template literals (`"\" + x"` and `"0"` as an argument) might be unfamiliar to some developers. Template literals provide a more readable way to concatenate strings with variables.

**Other Alternatives**

If you need alternative approaches for string padding, consider:

1.  **padEnd**: Similar to `padStart`, but pads the right side of the string instead.
2.  **stringRepeat() or repeat() function**: Introduced in ECMAScript 2015 (ES6), this function creates a new string by repeating an existing string.

Keep in mind that these alternatives might have different performance characteristics, compatibility issues, or use cases depending on your specific requirements.

In summary, the benchmark compares two methods for padding strings: `padStart` and the `splice` method used as a workaround. The choice of method depends on your target audience, compatibility needs, and personal preference for readability and performance.

Related benchmarks:

padStart vs splice (version: 0)

Measures speed between using padStart and splice

Comparing performance of: padStart vs splice

Created: 3 years ago by: Guest

Jump to the latest result

padStart

splice

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):