Mastering `is.boolean` for Type Checking in JavaScript with 'thiis': Fun Examples and Useful Tips
Tags: javascript, security, typescript, coding
Published: 2023-11-05 17:22:01

JavaScript is a dynamic and versatile programming language that's known for its flexibility. As a developer, it's essential to make sure your code can handle different data types accurately. In this article, we'll explore the `is.boolean` method provided by the "thiis" package, a fantastic tool designed to help you check if a value is a boolean with ease.

## Understanding Booleans in JavaScript

Before we dive into the exciting world of the `is.boolean` method, let's quickly brush up on what booleans are in JavaScript. Booleans are a special type of data with just two possible values: `true` and `false`. They're like the "on/off" switches of your code and play a crucial role in decision-making.

## Meet the `is.boolean` Method
[Documentation link](https://karbashevskyi.github.io/thiis/docs/API/Boolean/is.boolean)

The `is.boolean` method is not a native JavaScript feature, but it's a handy tool provided by the "thiis" package. It simplifies the process of checking if a given value is a boolean. This comes in super handy when you need to make sure a variable or input meets the criteria of being a boolean value.

> https://karbashevskyi.github.io/thiis/docs/API/Boolean/is.boolean

Let's see how the `is.boolean` method works in action:

```javascript
import { is } from 'thiis'; // Import the "is" object from the "thiis" package

// Using the `is.boolean` method
const myBoolean = true;
const result = is.boolean(myBoolean);

console.log(result); // true
```

In this example, we import the "is" object from the "thiis" package and use the `is.boolean` method to check if `myBoolean` is a boolean. As you might expect, it returns `true`.

## Real-World Scenarios with Fresh Examples

Now, let's dive into some practical examples to see how the `is.boolean` method can make your coding life easier and more fun.

### 1. **Form Validation**

Imagine you're working on a form, and you want to check if a checkbox or radio button is checked. You can use the `is.boolean` method to handle this:

```javascript
import { is } from 'thiis';

const formInput = document.querySelector('#checkboxInput');
const isChecked = is.boolean(formInput.checked);

if (isChecked) {
  // Celebrate the checked state!
} else {
  // Handle the unchecked state with grace.
}
```

### 2. **Dealing with API Responses**

When you're working with APIs, data can come in all shapes and sizes. With the `is.boolean` method, you can ensure that a specific property in the API response is a valid boolean:

```javascript
import { is } from 'thiis';

fetch('https://api.example.com/data')
  .then(response => response.json())
  .then(data => {
    const isValid = is.boolean(data.isActive);

    if (isValid) {
      // Party time for the isActive property!
    } else {
      // Deal with the unexpected like a champ.
    }
  });
```

### 3. **Rocking Conditional Logic**

Before you unleash your conditional statements, make sure the condition you're evaluating is a bona fide boolean:

```javascript
import { is } from 'thiis';

const isUserLoggedIn = true;

if (is.boolean(isUserLoggedIn)) {
  // Your code for handling a boolean condition can shine.
} else {
  // Handle other cases gracefully.
}
```

### 4. **Data Transformations**

When you're juggling data, use the `is.boolean` method to ensure that specific data points meet your criteria, especially when you're doing data gymnastics:

```javascript
import { is } from 'thiis';

function transformData(data) {
  if (is.boolean(data.isFeatured)) {
    // Shine the spotlight on data.isFeatured.
  } else {
    // Handle the rest of the data gracefully.
  }
}
```

### 5. **Array Adventures**

The `is.boolean` method can also accompany you on your array-checking adventures. Use `every()` to make sure all elements are booleans and `some()` to check if at least one isn't:

```javascript
import { is } from 'thiis';

const booleanArray = [true, false];
const mixedArray = [true, false, 0];

const areAllBooleans = booleanArray.every(is.boolean); // true
const hasNonBoolean = mixedArray.some(is.not_boolean); // true

console.log(areAllBooleans);
console.log(hasNonBoolean);
```

### 6. **Stream Stories**

If you're into streams and libraries like RxJS, the `is.boolean` method is your trusted companion. Use the `filter()` operator to ensure that your stream only emits glorious boolean values:

```javascript
import { is } from 'thiis';
import { from } from '

rxjs';
import { filter } from 'rxjs/operators';

const stream$ = from([true, false, 'not a boolean', true, 123, false]);

stream$
  .pipe(
    filter(is.boolean)
  )
  .subscribe(value => {
    console.log(value); // Only the true and false values will join the party!
  });
```

In this scenario, we create an observable stream (`stream$`) that emits various values. The `filter(is.boolean)` operator ensures that only boolean values are invited to the party, and the `subscribe` function logs their adventures.

## Wrapping It Up

The `is.boolean` method from the "thiis" package is your trusty sidekick in the world of JavaScript development. It streamlines type checking and ensures your code plays nice with the data types you expect. By adding the "thiis" package to your JavaScript projects and exploring its documentation for more tips and examples, you can become a master of precise type checking in JavaScript, all while having fun. The new examples provided in this article showcase the versatility and power of this method in real-world scenarios. Enjoy using it on your coding adventures!

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