Benchmark: + vs Number - MeasureThat.net

Tests:

Class cast
['1', '2', '3', '4'].map(Number)
+Cast
['1', '2', '3', '4'].map(x => +x)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Class cast
+Cast

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 119 on Android

View result in a separate tab

Test name	Executions per second
Class cast	3550569.0 Ops/sec
+Cast	8835208.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition:**
The benchmark is comparing two approaches to convert strings to numbers in JavaScript:

1. `+` operator (also known as "numeric coercion" or "implicit type conversion")
2. `Number()` function

The script uses an array of strings `['1', '2', '3', '4']` and applies one of the above methods to each element.

**Options Compared:**

* **+ operator**: Uses implicit type conversion, where JavaScript tries to convert a string to a number based on its value.
	+ Pros:
		- Fast execution, as it's a built-in operation.
		- Simple implementation.
	+ Cons:
		- May not work correctly for non-numeric strings (e.g., `NaN`).
		- Can lead to unexpected behavior when used with certain data types (e.g., NaN, Infinity).
* **Number() function**: A explicit function call to convert a string to a number.
	+ Pros:
		- More predictable and controlled outcome.
		- Works correctly for all strings, including non-numeric ones (returns `NaN` or `Infinity` accordingly).
	+ Cons:
		- Slightly slower execution due to the extra function call.

**Library Used:**
In this benchmark, no specific library is used. The script only relies on built-in JavaScript functions and operators.

**Special JS Feature/Syntax:**
There's a subtle aspect of interest here. When using the `+` operator with a string, JavaScript attempts to coerce it to a number based on its value. For example:

* `'1' + 2` would return `3`
* `'abc' + 2` would return `"abc2"`
* `NaN + 2` would return `NaN`

In contrast, the `Number()` function always returns a number, even if the input string is not numeric. This difference can lead to unexpected behavior when working with strings that might be converted to numbers.

**Other Alternatives:**

If you wanted to write this benchmark, you could also consider using other methods for converting strings to numbers:

* `parseInt()`: Similar to `Number()`, but it returns `NaN` if the input string is not a valid integer.
* `parseFloat()`: Converts a string to a floating-point number. It's similar to `Number()` but allows decimal points in the input string.

However, since the benchmark specifically compares the `+` operator and `Number()` functions, these alternatives would deviate from the original comparison and might not be suitable for this specific use case.

In summary, the benchmark is testing two approaches to convert strings to numbers: the implicit `+` operator coercion and the explicit `Number()` function. The results show that `Number()` outperforms the `+` operator in terms of execution speed, but it's also more predictable and controlled.

Related benchmarks:

+ vs Number (version: 0)

Comparing performance of: Class cast vs +Cast

Created: 2 years ago by: Registered User

Jump to the latest result

Class cast

+Cast

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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