Benchmark: X.Y string to Number vs parseFloat vs +0 vs /...

Script Preparation code:

var strA = "1912.62";
var strB = "1912.63";

Tests:

Number
var res = Number(strA);
parseFloat
var res = parseFloat(strA);
*1
var res = strA * 1;
-0
var res = strA - 0;
+
var res = +strA;
<<0
var res = strA<<0;
/1
var res = strA / 1;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Number
parseFloat
*1
-0
+
<<0
/1

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36

Browser/OS: Chrome 114 on Windows

View result in a separate tab

Test name	Executions per second
Number	2722250.8 Ops/sec
parseFloat	2351655.2 Ops/sec
*1	3996423.8 Ops/sec
-0	3840483.2 Ops/sec
+	3515402.0 Ops/sec
<<0	3271906.5 Ops/sec
/1	3412005.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its test cases.

**Benchmark Overview**

The benchmark is designed to compare different ways of converting a string representation of a number to a JavaScript Number or parseFloat value. The goal is to determine which method is the most efficient in terms of performance.

**Test Cases**

Each test case represents a single iteration of the conversion process, with slight variations:

1. `Number`: Converts a string to an integer using the built-in `Number()` function.
2. `parseFloat`: Converts a string to a floating-point number using the `parseFloat()` function.
3. `*1`: Multiplies the input string by 1, effectively converting it to a number.
4. `-0`: Adds 0 to the input string and then subtracts 0 again, which is equivalent to converting the original string to an integer using the unary plus operator (`+`).
5. `+`: Uses the unary plus operator (`+`) to convert the input string to a number.
6. "<<0"`: Shifts the bits of the input string to the left by 0 places, effectively converting it to an integer.
7. `/1`: Divides the input string by 1, which is equivalent to converting it to a number.

**Options Comparison**

Here's a brief comparison of each option:

* `Number()` and `parseFloat()` are built-in functions that perform explicit conversions from strings to numbers. They can be optimized for performance but may have additional overhead due to function calls.
* `*1` and `<<0` use implicit conversion mechanisms, which might be faster since they don't involve explicit function calls. However, these methods might not always work as expected, especially with non-numeric input strings.
* `-0` uses a clever trick to convert the string to an integer using the unary plus operator (`+`). This method is likely to be fast and efficient.

**Pros and Cons**

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

* `Number()` and `parseFloat()`:
	+ Pros: Built-in functions, easy to understand, and well-documented.
	+ Cons: May have additional overhead due to function calls, might not be as fast as other methods.
* `*1` and `<<0`:
	+ Pros: Fast and efficient, potentially suitable for numeric input strings.
	+ Cons: May not work correctly with non-numeric input strings, requires careful handling of edge cases.
* `-0`:
	+ Pros: Clever trick to convert string to integer using unary plus operator (`+`), likely fast and efficient.
	+ Cons: Requires careful handling of edge cases, might not be immediately clear to readers.

**Library Usage**

There are no libraries used in this benchmark. The tests rely solely on built-in JavaScript functions and operators.

**Special JS Features or Syntax**

None mentioned.

**Alternatives**

Other alternatives for performing conversions between strings and numbers include:

* Using regular expressions to extract numeric values from input strings
* Implementing custom parsing logic using switch statements or object literals
* Leveraging specialized libraries like ` numeral.js` or ` parse-value`

Keep in mind that each alternative has its pros and cons, and the best choice depends on the specific requirements and constraints of your project.

I hope this explanation helps!

Related benchmarks:

X.Y string to Number vs parseFloat vs +0 vs /... (version: 0)

Comparing performance of: Number vs parseFloat vs *1 vs -0 vs + vs <<0 vs /1

Created: one year ago by: Guest

Jump to the latest result

Number

parseFloat

*1

-0

+

<<0

/1

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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