Benchmark: isNumber vs unary cast

HTML Preparation code:

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/2.4.1/lodash.min.js"></script>

Tests:

map + find
var output = _.isNumber('a') && _.isNumber('123') console.log(output);
reduce + includes
var output = +'a' === +'a' && +'123' === +'123' console.log(output);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map + find
reduce + includes

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser/OS: Chrome 122 on Windows

View result in a separate tab

Test name	Executions per second
map + find	123125.8 Ops/sec
reduce + includes	129592.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring the performance of JavaScript code is crucial in understanding how different implementations and libraries can impact execution speed.

The provided benchmark definition json shows that it's testing two different approaches to comparison: using the `_.isNumber` function from Lodash library and a simple unary cast.

**Options being compared:**

1.  **Lodash's `_.isNumber`**: This function checks if a value is a number.
2.  **Unary cast**: This approach uses a simple cast operation to check for equality between two strings.

**Pros and Cons of each approach:**

*   **Lodash's `_.isNumber`:**
    *   Pros:
        *   More accurate, as it can handle non-numeric values like NaN (Not a Number) or complex numbers.
        *   Less prone to errors, as the function explicitly checks for numeric values.
    *   Cons:
        *   Adds overhead due to the extra function call and potential additional parsing steps in some implementations.
*   **Unary cast:**
    *   Pros:
        *   Fast and lightweight, with minimal overhead compared to a dedicated function like `_.isNumber`.
    *   Cons:
        *   May return incorrect results for non-numeric values, especially if the implementation relies on implicit type conversions.

**Other considerations:**

*   **Browser behavior:** The choice of comparison method may affect browser behavior in certain cases. For instance, some browsers might optimize unary casts as a faster operation compared to function calls like `_.isNumber`.
*   **Library dependencies:** Using an external library like Lodash adds dependency and potential overhead due to the need for loading the library.

**Test users special JS feature or syntax:**

There is no apparent use of any special JavaScript features or syntax in these benchmark cases. The comparison methods mentioned are quite basic.

**Other alternatives:**

If you needed more options, there would be several approaches to compare values:

*   **Number()**: A global function that attempts to convert a value to an integer.
*   **Finite()**: Checks if a value is finite (not NaN) before attempting to convert it to a number.
*   **toString() + parseFloat()**: Converts the string representation of the value and then parses it as a float.

Keep in mind, each approach has its pros and cons as explained earlier.

Related benchmarks:

isNumber vs unary cast (version: 0)

Comparing performance of: map + find vs reduce + includes

Created: 2 years ago by: Guest

Jump to the latest result

map + find

reduce + includes

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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