Benchmark: Capitalize first char of a string 2

HTML Preparation code:


<script src=''></script>

Script Preparation code:

var lower = 'this is an entirely lowercase string';

Tests:

charAt
var upper = lower.charAt(0).toUpperCase() + lower.substr(1);
anon function
const upper = lower.replace(/^\w/, c => c.toUpperCase());
function
var upper = lower.replace(/^\w/, function (chr) { return chr.toUpperCase(); });
charAt + slice
var upper = lower.charAt(0).toUpperCase() + lower.slice(1);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
charAt
anon function
function
charAt + slice

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

The provided JSON represents a benchmark definition, which consists of four main components:

1. **Name**: A unique identifier for the benchmark.
2. **Description**: An optional text description of the benchmark (empty in this case).
3. **Script Preparation Code**: A JavaScript code snippet that sets up a variable `lower` with a specific value ("this is an entirely lowercase string").
4. **Html Preparation Code**: An HTML snippet that includes a script tag, but it's empty in this case.

**Test Cases**

The benchmark definition has four individual test cases, each represented as a separate JSON object. Each test case defines a different approach to capitalize the first character of the `lower` string:

1. **charAt**: Uses the `charAt()` method to access the first character and then uses `toUpperCase()` to convert it.
2. **anon function**: Uses an anonymous function (an immediately invoked function expression, or IIFE) as a replacement for the regular expression in the `replace()` method.
3. **function**: Uses a named function as a replacement for the anonymous function in the `replace()` method.
4. **charAt + slice**: Combines the `charAt()` and `slice()` methods to achieve the same result.

**Library**

There is no explicit library mentioned in the benchmark definition, but some libraries are used implicitly:

* The `replace()` method uses a regular expression, which is a built-in JavaScript function.
* The `charAt()` method is a standard JavaScript method for accessing character indices of strings.

**Special JS Feature or Syntax**

The only special feature or syntax used in this benchmark is the use of an anonymous function (IIFE) in test case 2. This allows for more fine-grained control over the replacement logic without polluting the global scope.

**Pros and Cons of Different Approaches**

Here's a brief summary of the pros and cons of each approach:

1. **charAt**: Simple and efficient, but may be slower due to the additional function call.
	* Pros: Easy to implement, fast execution time.
	* Cons: May incur overhead from the `toUpperCase()` method.
2. **anon function**: Provides more control over the replacement logic, but may be slightly slower due to the added complexity.
	* Pros: More flexible and customizable, can avoid global scope pollution.
	* Cons: Slightly slower execution time, requires understanding of anonymous functions.
3. **function**: Similar to `anon function`, but with a named function, which may provide better readability and maintainability.
	* Pros: Easier to understand and debug, can be more readable than anonymous functions.
	* Cons: May incur additional overhead due to the named function declaration.
4. **charAt + slice**: Combines two standard methods for efficient execution time.
	* Pros: Fastest execution time among all approaches, easy to implement.
	* Cons: Requires understanding of both `charAt()` and `slice()` methods.

**Other Alternatives**

Some alternative approaches that could be explored in this benchmark include:

* Using a regex with the `replace()` method with a capturing group to extract the first character.
* Utilizing a library like Lodash or Underscore.js, which provides more functional programming-style utilities for string manipulation.
* Exploring other methods like `substr()` or `substring()` to achieve the same result.

These alternative approaches can help highlight different trade-offs and optimize performance in various use cases.

Related benchmarks:

Capitalize first char of a string 2 (version: 0)

Comparing performance of: charAt vs anon function vs function vs charAt + slice

Created: 7 years ago by: Guest

Jump to the latest result

charAt

anon function

function

charAt + 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):