Benchmark: To Formatted Number

Script Preparation code:


var arr = ['a', 10000, 100.123, "1000", "1,123.123", "", undefined];

Tests:

function cb
function formattedNumber(n = 0) { let num = n; if (typeof num === "string") { num = Number(num.replace(",", "")); if (isNaN(num)) { // return the original string if not a valid number return n; } } return num.toLocaleString("en-US", { maximumFractionDigits: 4 }); } arr.forEach(formattedNumber)
arrow
function formattedNumber(n) { // TODO: consider using toLocaleString if (parseInt(n) === 0) { return "0"; } else { return (n || "").toString().replace(/\B(?=(\d{3})+(?!\d))/g, ","); } } arr.forEach(formattedNumber)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
function cb
arrow

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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I'll break down the provided JSON and explain what's tested, compared, and other considerations.

**Benchmark Definition**

The benchmark is testing two functions that format numbers to a specific string representation: `formattedNumber` (function cb) and another anonymous function (arrow). The goal is to compare their performance in formatting numbers with different input types (integer, float, string).

**Options Compared**

Two approaches are compared:

1.  **Function cb**: This function takes an optional parameter `n = 0`. It checks if the input `num` is a string and performs a replacement operation on it. If the resulting value is not NaN, it returns the formatted number using `toLocaleString`.
2.  **Arrow Function**: This anonymous function also takes a single input `n`. It first checks if `parseInt(n) === 0`, returning "0" immediately if true. Otherwise, it converts the input to a string and replaces commas with periods using a regular expression.

**Pros and Cons**

Here are some pros and cons of each approach:

*   **Function cb**:
    *   Pros:
        *   Handles string inputs more explicitly.
        *   Uses `toLocaleString` for formatting, which is generally considered more accurate and user-friendly.
    *   Cons:
        *   Has an optional parameter (`n = 0`) that might not be used in all cases.
*   **Arrow Function**:
    *   Pros:
        *   More concise and uses fewer lines of code.
        *   Directly checks if the input is zero and returns immediately.
    *   Cons:
        *   Uses a regular expression for formatting, which can be less accurate than `toLocaleString`.
        *   Does not handle string inputs explicitly.

**Library: toLocaleString**

The `toLocaleString` method is used by both functions in its respective implementations. It's a built-in JavaScript method that converts a number to a string according to the locale and options provided. In this case, it's used with the maximumFractionDigits option set to 4, which means it will format numbers with up to four decimal places.

**Special JS Feature or Syntax**

The `toLocaleString` method uses internationalization features, but it doesn't use any specific JavaScript feature or syntax that's unique to modern browsers. However, its usage is a good example of how built-in methods can be used for formatting and formatting numbers in a locale-specific way.

**Other Alternatives**

Some alternative approaches could have been considered:

*   **Using a library like Moment.js**: This popular date and time manipulation library provides a function called `format` that formats numbers with a specific format, similar to what's done by the `toLocaleString` method.
*   **Implementing custom formatting logic**: Instead of using built-in methods or libraries, developers could implement their own custom formatting logic using regular expressions and string manipulation.

In general, when testing JavaScript performance benchmarks, it's essential to consider factors like:

*   Function complexity and conciseness
*   Use of built-in methods versus custom implementation
*   Input handling and edge cases
*   Browser-specific features or quirks

Related benchmarks:

To Formatted Number (version: 0)

Comparing performance of: function cb vs arrow

Created: 4 years ago by: Guest

Jump to the latest result

function cb

arrow

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):