Benchmark: JS substring vs slice

Script Preparation code:

var string = "I am the god of hellfire, and I bring you..."

Tests:

slice
var substring = string.slice(17, -11);
substring
var substring = string.substring(17, string.length - 11);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
substring

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser/OS: Chrome 125 on Linux

View result in a separate tab

Test name	Executions per second
slice	13341887.0 Ops/sec
substring	7387454.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll explain the JavaScript microbenchmark test case you provided.

**Benchmark Overview**

The benchmark compares two approaches to extract a substring from a given string: using `slice()` and `substring()`. The goal is to measure which approach is faster in terms of executions per second (EPS) on various browsers and devices.

**Options Compared**

Two options are compared:

1. **`slice()`**: A method that returns a new string by extracting a portion of another string, starting at the specified start index and ending at the specified end index.
2. **`substring()`**: A method that returns a new string by extracting a portion of another string, starting at the specified start index and ending at the specified length.

**Pros and Cons**

* **`slice()`**:
	+ Pros: More concise syntax, can be used with numeric indexes to extract from an array.
	+ Cons: May have performance implications if not used correctly (e.g., using negative indices).
* **`substring()`**:
	+ Pros: Allows for more flexibility in specifying the end index (can use a length parameter instead of an index).
	+ Cons: More verbose syntax, may be slower due to additional overhead.

In general, `slice()` is considered faster and more efficient because it uses a single array operation to extract the substring. However, `substring()` can be beneficial when working with strings that contain spaces or non-ASCII characters, as it allows for more flexible indexing.

**Library Usage**

None of the test cases explicitly use any libraries beyond JavaScript's built-in `string` and `array` methods.

**Special JS Features/Syntax**

There are no special features or syntax used in this benchmark. The focus is on comparing two standard JavaScript string extraction methods.

**Other Considerations**

To ensure accurate results, it's essential to:

* Use identical input strings for both options being compared.
* Minimize any additional operations that might affect performance (e.g., using `trim()` or `toUpperCase()`).
* Run the benchmark multiple times with different devices and browsers to account for variability.

**Alternatives**

If you need to test other string extraction methods or approaches, consider exploring:

1. **`indexOf()`**: A method that finds the index of a substring within another string.
2. **Regular expressions (regex)**: A powerful way to search and manipulate strings using pattern matching rules.
3. **DOM string manipulation libraries**: Libraries like jQuery's `$.trim()` or other DOM-specific string manipulation functions.

Keep in mind that each alternative approach may have its own trade-offs, performance characteristics, and use cases.

Related benchmarks:

JS substring vs slice (version: 0)

Comparing performance of: slice vs substring

Created: 2 years ago by: Guest

Jump to the latest result

slice

substring

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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