Benchmark: padStart vs repeat start

Tests:

PadStart
let x = "." return x.padStart(101, " ")
Repeat
let x = "." return " ".repeat(100) + x

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
PadStart
Repeat

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36 Edg/141.0.0.0

Browser/OS: Chrome 141 on Windows

View result in a separate tab

Test name	Executions per second
PadStart	11563638.0 Ops/sec
Repeat	10987738.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is essential to ensure that our code runs efficiently and effectively. Let's dive into the world of BenchmarkThat.net.

**Benchmark Definition**
The provided JSON defines two benchmark tests: `padStart` and `repeat`. The main difference between these tests lies in how they manipulate strings using pad-related methods.

1. **PadStart**: In this test, a string is padded with spaces (`" "`) to a specific length (101) using the `padStart()` method.
2. **Repeat**: This test uses the `repeat()` method to create a string of a specified length (100) and then appends the original empty string.

**Options being compared**
The benchmark compares two approaches:

1. **`padStart()`**: A method that pads a string from the left with spaces until it reaches a specified length.
2. **`repeat()`**: A method that creates a new string by repeating an existing string for a specified number of times.

**Pros and Cons**

* `padStart()`:
	+ Pros: Can be more efficient than using `repeat()`, as it avoids creating multiple strings.
	+ Cons: Requires an explicit length, which can lead to typos or errors if the length is not correctly specified.
* `repeat()`:
	+ Pros: Easy to use and flexible, as it allows for any string and repeat count.
	+ Cons: Can be slower than `padStart()` due to the overhead of creating multiple strings.

**Library**
The benchmark does not rely on a specific JavaScript library. It tests the built-in methods provided by modern JavaScript engines.

**Special JS feature or syntax**
None mentioned in this case. However, it's worth noting that some older browsers might have different string manipulation methods or behaviors compared to modern engines like V8 (used by Chrome and Node.js).

**Other alternatives**

For more complex string manipulation tasks, you may need to use other libraries or polyfills, such as:

* `string-padding`: A library specifically designed for padding strings.
* `repeat-string`: Another library that provides a simple way to repeat strings.

Keep in mind that the choice of alternative depends on your specific requirements and constraints.

**Benchmark preparation code**
The provided JSON does not include any script or HTML preparation code. This is likely because the benchmark aims to test only the JavaScript engine's string manipulation performance, without considering other factors like DOM rendering or event handling.

By running these benchmarks, you can gain insights into how different JavaScript engines handle string padding and repetition, which can inform your coding decisions and help optimize your applications for better performance.

Related benchmarks:

padStart vs repeat start (version: 0)

Comparing performance of: PadStart vs Repeat

Created: 2 years ago by: Guest

Jump to the latest result

PadStart

Repeat

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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