Benchmark: Multiple cast - MeasureThat.net

Script Preparation code:

var ARRAY = [1, '1','22','-']

Tests:

double cast
for (var i=0; i< ARRAY.length; i++){ var val = ARRAY[i]; val = isNaN(Number(val)) ? val : Number(val) }
one cast
for (var i=0; i< ARRAY.length; i++){ var val = ARRAY[i]; var casted = Number(val); val = isNaN(casted) ? val : casted }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
double cast
one cast

Fastest: N/A

Slowest: N/A

Latest run results:

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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, compared options, pros and cons, and other considerations.

**Benchmark Overview**

The benchmark measures the performance of two different approaches to casting numeric values in JavaScript: single casting (`one cast`) and double casting (`double cast`).

**Script Preparation Code**

The script preparation code defines an array `ARRAY` with a mix of numbers and strings:
```javascript
var ARRAY = [1, '1','22','-'];
```
This array is used as input for the benchmark.

**Html Preparation Code**

There is no HTML preparation code provided, which means that only JavaScript performance is being measured.

**Test Cases**

The two test cases are:

### "double cast"

```javascript
for (var i=0; i< ARRAY.length; i++){\r\n  var val = ARRAY[i];\r\n  val = isNaN(Number(val)) ? val : Number(val)\r\n}
```
This approach casts the value `val` to a number using `Number()` and then checks if it's NaN (Not a Number) using `isNaN()`. If it is, the original value `val` is used.

### "one cast"

```javascript
for (var i=0; i< ARRAY.length; i++){\r\n  var val = ARRAY[i];\r\n  var casted = Number(val);\r\n  val = isNaN(casted) ? val : casted\r\n}
```
This approach casts the value `val` to a number using `Number()` and assigns it to a new variable `casted`. The original value `val` is then checked if it's NaN using `isNaN()`, and if it is, the casted value `casted` is used.

**Comparison**

The main difference between these two approaches is when the casting happens:

* In "double cast", the casting happens first, and then the result is checked.
* In "one cast", the casting happens second, after the original value has already been assigned to a variable.

**Pros and Cons**

### "Double Cast"

Pros:

* May be faster because it avoids assigning an intermediate result to a variable
* Reduces the number of `isNaN()` checks

Cons:

* Requires two operations: casting and checking
* May cause unnecessary overhead due to the repeated checks

### "One Cast"

Pros:

* Reduces the number of `isNaN()` checks (only one check per iteration)
* May be faster because it avoids assigning an intermediate result to a variable

Cons:

* Requires three operations: accessing the array, casting, and checking
* Can lead to slower performance due to the repeated checks

**Other Considerations**

* The use of `isNaN()` checks assumes that the input values are either numbers or strings. If other types of values are present, additional checks may be necessary.
* The choice of data type for the variable `val` (number or string) depends on the specific requirements of the application.

**Library and Special JS Feature**

There is no library being used in this benchmark. However, the use of the `Array.prototype.forEach()` loop is a standard JavaScript feature that's widely supported across browsers.

**Alternatives**

Other approaches to casting numeric values in JavaScript include:

* Using a separate function to perform the casting
* Using a switch statement or object-based approach to handle different data types
* Using a library like Lodash or Moment.js for date and number manipulation

Keep in mind that these alternatives may have different trade-offs in terms of performance, readability, and maintainability.

Related benchmarks:

Multiple cast (version: 0)

Comparing performance of: double cast vs one cast

Created: 3 years ago by: Registered User

Jump to the latest result

double cast

one cast

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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