Navigating JavaScript with Ease: Unveiling `is.null` and `is.not_null` from 'thiis'
Tags: javascript, typescript, beginners, programming
Published: 2023-11-24 08:16:40

JavaScript, the realm of endless possibilities, sometimes requires us to decipher the mysteries of null values. Fear not, for the 'thiis' package brings two trusty companions to your aid: `is.null` and `is.not_null`. In this delightful journey, we'll explore these tools, uncovering their magic and weaving them into the fabric of everyday JavaScript adventures.

## Embracing the Null Quest


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/r0fo32np7jpi0yv72923.jpeg)

Before we embark on our quest, let's grasp the concept of null in JavaScript. Null is a special value that represents the absence of a value or a variable that has been declared but not assigned any value. Identifying and handling null is crucial for building robust and error-free code.

## Meet `is.null` - Your Null Navigator

[Documentation link](https://karbashevskyi.github.io/thiis/docs/API/Common/is.null)

Imagine you're on a grand quest to find null values in your code. The `is.null` method acts as your trustworthy navigator, ensuring that a value is indeed null. Let's witness it in action:

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

const myValue = null;
const result = is.null(myValue);

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

In this example, we import the "is" object from the "thiis" package and use the `is.null` method to confirm that `myValue` is indeed null. As expected, it returns `true` because the value is indeed null.

## A Symphony of Examples

Now, let's compose a symphony of examples that showcase the versatility of `is.null` and its companion, `is.not_null`. We'll explore six unique scenarios, dancing through various landscapes of JavaScript.

### 1. **Embracing Null Values**

The primary role of `is.null` is to identify null values. Use it to gracefully handle situations where a value might be null:

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

const potentiallyNullValue = someFunctionThatMayReturnNull();

if (is.null(potentiallyNullValue)) {
  // Handle the null scenario gracefully.
} else {
  // Continue with confidence.
}
```

### 2. **Guarding Against Null**

Conversely, `is.not_null` is your guardian against null values. Ensure a value isn't null before proceeding:

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

const importantValue = someFunctionThatShouldNotBeNull();

if (is.not_null(importantValue)) {
  // Your guardian prevents null mishaps!
} else {
  // Time to explore other possibilities.
}
```

### 3. **Validating Inputs with `is.null`**

When working with user inputs, ensuring they are not null is essential. Use `is.null` to validate and prompt users to provide valid inputs:

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

function validateUserInput(input) {
  if (is.null(input)) {
    return 'Please provide a valid input.';
  } else {
    return 'Input validated successfully!';
  }
}
```

### 4. **Robust Conditionals with `is.not_null`**

Conditionals are at the heart of programming. Ensure a value is not null before executing specific actions with `is.not_null`:

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

const userChoice = getUserInput();

if (is.not_null(userChoice)) {
  // Execute actions for valid choices.
} else {
  // Handle other scenarios with grace.
}
```

### 5. **Stream of Clarity with `is.null`**

Let's embark on a stream adventure with RxJS. Using `filter` and `is.null`, ensure that the stream processes only null values:

```javascript
import { is } from 'thiis';
import { from } from 'rxjs';
import { filter } from 'rxjs/operators';

const stream$ = from([null, 'not null', undefined, 'another value', null]);

stream$
  .pipe(
    filter(is.null)
  )
  .subscribe(value => {
    console.log(value); // Only null values will be part of the stream's story.
  });
```

In this example, the `filter(is.null)` ensures that only null values get processed by the stream.

### 6. **Array Exploration with `is.not_null`**

Arrays are another playground for `is.not_null`. Use `every()` to confirm that all elements are not null and `some()` to check if at least one isn't:

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

const notNullArray = [1, 'not null', true];
const mixedArray = [null, 'not null', 0, undefined];

const allElementsNotNull = notNullArray.every(is.not_null); // true
const someElementsNotNull = mixedArray.some(is.not_null); // true

console.log(allElementsNotNull);
console.log(someElementsNotNull);
```

Here, `allElementsNotNull` checks if all elements in `notNullArray` are not null, and `someElementsNotNull` checks if at least one element in `mixedArray` is not null.

## The Adventure Continues

The `is.null` and `is.not_null` methods from the 'thiis' package are your reliable companions on your JavaScript adventure. They make null handling playful and precise, ensuring your code interacts with null values exactly as intended. By adding the 'thiis' package to your JavaScript toolkit and exploring its documentation for more tips and examples, you can navigate the JavaScript landscape with confidence and a touch of fun.

So, keep coding, and remember that JavaScript is a grand adventure waiting to unfold! And, as always, a big thank you to ChatGPT for making this article an enjoyable journey into the world of JavaScript null values.

> 🎗 ChatGPT & DALL·E 3