Benchmark: Implicit vs parseFloat vs Number string to num

Script Preparation code:

var strNum = '6969699.1'

Tests:

implicit
var imp = + strNum
parseFloat
var toStr = parseFloat(strNum)
Number
var num = Number(strNum)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
implicit
parseFloat
Number

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:123.0) Gecko/20100101 Firefox/123.0

Browser/OS: Firefox 123 on Linux

View result in a separate tab

Test name	Executions per second
implicit	1601476480.0 Ops/sec
parseFloat	26722464.0 Ops/sec
Number	1379750016.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark and its various aspects.

**Benchmark Definition**

The benchmark is designed to measure the performance of three different approaches for converting a string number to a numerical value in JavaScript: implicit conversion, `parseFloat()`, and `Number()`.

The test cases use the following script preparation code:
```javascript
var strNum = '6969699.1';
```
This code defines a variable `strNum` with the value `'6969699.1'`, which is a string representation of the decimal number 6,699,690.

**Test Cases**

There are three test cases:

1. **Implicit Conversion**: The first test case uses implicit conversion to convert the string to a number:
```javascript
var imp = + strNum;
```
In JavaScript, the `+` operator is used for both arithmetic and numeric conversions. This means that when the `+` operator encounters a string literal, it attempts to interpret the entire string as a single number.

2. **parseFloat()**: The second test case uses the `parseFloat()` function to convert the string to a floating-point number:
```javascript
var toStr = parseFloat(strNum);
```
The `parseFloat()` function is used to parse a string and return a floating-point number.

3. **Number()**: The third test case uses the `Number()` function to convert the string to an integer or float, depending on its value:
```javascript
var num = Number(strNum);
```
In JavaScript, the `Number()` function can take two arguments: a single value (which is converted to a number) and a radix argument (which specifies the base of the number in the range 1-36).

**Pros and Cons**

Here's a brief analysis of each approach:

* **Implicit Conversion**: This approach can be faster because it avoids the overhead of a separate function call. However, it may also introduce rounding errors due to the conversion process.
	+ Pros: potentially faster
	+ Cons: may introduce rounding errors
* **parseFloat()**: This approach is more explicit and less prone to rounding errors than implicit conversion. However, it may be slower because it involves an additional function call.
	+ Pros: more predictable results
	+ Cons: slower due to extra function call
* **Number()**: This approach can convert both integers and floats, but it may also introduce rounding errors if the input string is not a valid integer representation.
	+ Pros: versatile (converts integers and floats)
	+ Cons: may introduce rounding errors

**Library**

There are no external libraries used in this benchmark.

**Special JS Features or Syntax**

None of the test cases use any special JavaScript features or syntax beyond what's commonly available in modern browsers.

**Other Alternatives**

If you were to compare these approaches on a different platform, such as Node.js or a web framework like React Native, you might also consider using other methods like:

* **Big.js**: A library for big numbers and decimal arithmetic.
* **Decimal.js**: Another library for decimal arithmetic.
* **Arbitrary-precision arithmetic libraries** (e.g., `big.js`, `decimal.js`): These libraries can provide more precise control over the conversion process, especially when working with very large or small numbers.

However, in general web browsers are unlikely to be a bottleneck for these kinds of conversions, and the differences between these approaches will likely be relatively small.

Related benchmarks:

Implicit vs parseFloat vs Number string to num (version: 0)

Comparing performance of: implicit vs parseFloat vs Number

Created: 3 years ago by: Guest

Jump to the latest result

implicit

parseFloat

Number

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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