Benchmark: parseInt vs Number vs implicit conversion

Script Preparation code:

var intA = 42.034;
var strB = "42.034";

Tests:

Implicit conversion
var res = intA + +strB;
parseInt
var res = parseInt(intA) + parseInt(strB);
Number
var res = Number(intA) + Number(strB);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Implicit conversion
parseInt
Number

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36

Browser/OS: Chrome 136 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Implicit conversion	242620880.0 Ops/sec
parseInt	161231424.0 Ops/sec
Number	237572816.0 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 and explain what's being tested.

**Benchmark Overview**

The benchmark measures the performance of three different approaches to perform implicit conversions in JavaScript:

1. Using the `+` operator (also known as "implicit conversion" or "type coercion").
2. Using the `parseInt()` function.
3. Using the `Number()` function.

**Test Case Explanation**

Each test case is a separate benchmark that tests one of these three approaches. The input variables are:

* `intA`: an integer literal (`42.034`)
* `strB`: a string literal containing a decimal number (`"42.034"`)

The output variable, `res`, is the sum of the two inputs.

**Implicit Conversion (Test Case 1)**

This test case uses the `+` operator to concatenate and implicitly convert the string to a number. The JavaScript engine will attempt to convert the string "42.034" to a decimal number behind the scenes.

Pros:

* Simple and easy to implement.
* Works well for most cases, as the JavaScript engine is capable of handling implicit conversions.

Cons:

* Can lead to unexpected behavior if the input string has leading zeros or other formatting that affects its interpretation as a number.
* May be slower due to the overhead of type coercion.

**parseInt() (Test Case 2)**

This test case uses the `parseInt()` function to explicitly convert the integer literal to an integer. The second argument is set to `10`, which means the conversion will be base-10 (decimal).

Pros:

* Provides explicit control over the conversion process.
* Can handle edge cases more accurately, as it allows the developer to specify the radix.

Cons:

* Requires additional function calls and arguments, which can add overhead.
* May not work well for all input types or formats.

**Number() (Test Case 3)**

This test case uses the `Number()` function to explicitly convert the string literal to a decimal number. This is similar to using `parseInt()`, but it allows the conversion to be base-10 by default.

Pros:

* Simplifies the conversion process compared to `parseInt()`.
* Works well for most cases, as the JavaScript engine can handle implicit conversions.

Cons:

* May not provide explicit control over the conversion process.
* Can lead to unexpected behavior if the input string has leading zeros or other formatting that affects its interpretation as a number.

**Library Considerations**

None of the test cases use any external libraries.

**Special JS Feature/Syntax**

The benchmark uses the `+` operator for implicit conversions, which is a built-in JavaScript feature. The `parseInt()` and `Number()` functions are also standard JavaScript functions.

**Other Alternatives**

If you want to explore alternative approaches, here are some additional options:

* Using `parseFloat()` instead of `+` or `parseInt()` for floating-point numbers.
* Using regular expressions (e.g., `\d+(\.\d+)?`) to extract numeric values from strings.
* Using a dedicated library like `lodash` or `moment.js` for string manipulation and conversion.

These alternatives can provide more flexibility, control, or performance in specific use cases, but may also introduce additional overhead or complexity.

Related benchmarks:

parseInt vs Number vs implicit conversion (version: 0)

Comparing performance of: Implicit conversion vs parseInt vs Number

Created: 4 years ago by: Guest

Jump to the latest result

Implicit conversion

parseInt

Number

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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