Benchmark: substr vs substring vs slice

Script Preparation code:

var shortLength = 200;
var shortStr = new Array(300 + 1).join('s');
var longLength = 2000;
var longStr = new Array(3000 + 1).join('l');

Tests:

substr
shortStr.substr(0, shortLength); longStr.substr(0, longLength);
substring
shortStr.substring(0, shortLength); longStr.substring(0, longLength);
slice
shortStr.slice(0, shortLength); longStr.slice(0, longLength);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
substr
substring
slice

Fastest: N/A

Slowest: N/A

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

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Let's break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The benchmark is testing three different approaches to extract a substring from a string:

1. `substr`: The original `substr` method in JavaScript.
2. `substring`: The `substring` method introduced in ECMAScript 2015 (ES6) for extracting substrings.
3. `slice`: The `slice` method, which is similar to `substr` but can also extract a part of an array.

**Script Preparation Code**

The script preparation code generates two strings:

* `shortStr`: A string with a length of approximately 300,000 characters (created using an array and the `join()` method).
* `longStr`: A string with a length of approximately 3,000,000 characters (similar to `shortStr`, but larger).

These strings are used as inputs for the three test cases.

**Test Cases**

Each test case consists of two lines:

```javascript
shortStr.substr(0, shortLength);
longStr.substr(0, longLength);
```

The first line extracts a substring from `shortStr` using the `substr` method, and the second line does the same for `longStr`.

**Library and Syntax**

There is no library used in this benchmark. The code relies on built-in JavaScript methods.

**Options Compared**

The options compared are:

* `substr`
* `substring` (ES6)
* `slice`

**Pros and Cons of Each Approach**

1. **substr**: This method has been around for a long time and is widely supported across browsers and platforms.
	* Pros: Simple, widely supported, and efficient.
	* Cons: Can be slow for large strings due to the need to calculate the substring length at runtime.
2. **substring** (ES6): Introduced in ECMAScript 2015, this method provides a more modern and efficient way to extract substrings.
	* Pros: Faster than `substr` for large strings, as it avoids calculating the substring length at runtime.
	* Cons: Requires support for ES6 syntax, which may not be available on older browsers or platforms.
3. **slice**: This method is similar to `substr` but can also extract a part of an array.
	* Pros: Similar performance to `substring`, as it avoids calculating the substring length at runtime.
	* Cons: May not be as widely supported as `substr`, especially in older browsers or platforms.

**Other Considerations**

When choosing between these methods, consider the following:

* If you need support for older browsers or platforms that don't support ES6 syntax, use `substr`.
* For modern web applications and browsers, use `substring` (ES6) if possible.
* If you're working with arrays, prefer `slice` over `substr`.

**Alternatives**

Other alternatives to these methods include:

* Regular expressions: You can use regular expressions to extract substrings from strings. However, this approach may be slower than the three methods compared.
* String manipulation libraries or functions: There are third-party libraries and functions available that provide more efficient substring extraction methods.

Related benchmarks:

substr vs substring vs slice (version: 0)

Comparing performance of: substr vs substring vs slice

Created: 2 years ago by: Guest

Jump to the latest result

substr

substring

slice

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):