Benchmark: Performance Test: substring vs substr vs slice: the sequel

Script Preparation code:

var string = "Hello, world! This is the greatest benchmark of the world!"

Tests:

slice
var substring = string.slice(3, 10);
substring
var substring = string.substring(3, 10);
substr
var substring = string.substr(3, 7);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
substring
substr

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36

Browser/OS: Chrome 74 on Mac OS X 10.14.5

View result in a separate tab

Test name	Executions per second
slice	14626082.0 Ops/sec
substring	12441154.0 Ops/sec
substr	12169680.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**What is being tested?**

The benchmark compares the performance of three different string manipulation methods in JavaScript: `slice()`, `substring()`, and `substr()` (note that `substr` is not a standard method in modern JavaScript; it's an older way to achieve the same result).

**Options compared:**

1. **Slice**: The `slice()` method returns a new string by extracting a section of another string.
2. **Substring**: The `substring()` method returns a new string by extracting a section of another string, starting from a specified start index and ending at a specified end index (exclusive).
3. **Substr** (older method): As mentioned earlier, `substr` is not a standard method in modern JavaScript. It's an older way to achieve the same result as `slice()` or `substring()`.

**Pros and cons of each approach:**

1. **Slice**:
	* Pros:
		+ Fast and efficient.
		+ Returns a new string, avoiding mutation of the original string.
	* Cons:
		+ Less readable than other methods (e.g., it requires knowing the length of the substring).
2. **Substring**:
	* Pros:
		+ More readable than `slice()`, as it clearly specifies start and end indices.
		+ Can be more intuitive for users who are familiar with this method.
	* Cons:
		+ May have performance overhead due to the creation of a new string object.
3. **Substr** (older method):
	* Pros: None notable, as it's not a standard method and has been largely replaced by `slice()` and `substring()`.
	* Cons:
		+ Less readable and maintainable than modern methods.

**Considerations:**

1. The use of older methods like `substr` is mainly for historical or educational purposes.
2. Modern JavaScript emphasizes immutability, and using `slice()` or `substring()` can help avoid mutating the original string.
3. Performance differences between these methods are likely to be small, as they all involve creating a new string object.

**Library usage:**

None of the provided benchmark cases uses any external libraries.

**Special JS features or syntax:**

There are no special JavaScript features or syntax mentioned in this benchmark that would require additional explanation.

**Alternatives:**

If you wanted to test alternative string manipulation methods, some examples might include:

1. **Regex**: Regular expressions can be used to extract substrings from a string.
2. **String.prototype.includes() and String.prototype.indexOf()**: These methods can be used to find the index of a substring within a larger string.
3. **Array methods**: If you were to work with an array of characters, you could use array methods like `map()` or `filter()` to achieve similar results.

Keep in mind that these alternatives might not be as efficient or readable as using `slice()`, `substring()`, or `substr()` (or modern equivalents), depending on the specific use case.

Related benchmarks:

Performance Test: substring vs substr vs slice: the sequel (version: 0)

Comparing performance of: slice vs substring vs substr

Created: 5 years ago by: Guest

Jump to the latest result

slice

substring

substr

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):