Quick Review of 5 Of The Most Powerful JavaScript Methods
Tags: html, webdev, javascript, codenewbie
Published: 2020-09-26 05:31:01


![Simple Technology Blog Banner (1).png](https://cdn.hashnode.com/res/hashnode/image/upload/v1601033107422/3P9T1nImg.png)
Hello 👋Everyone,

In this article, I am going to discuss 5 of the most powerful JavaScript methods.

Now, let's start discussing these methods one by one.

1. **Split:** 

This method is used to split a string into an array of substrings and it returns the new array. Splitting of a string is done by searching for a pattern where the pattern is provided as the first parameter in the method's call.

Let's take one example so that you can understand it clearly:

```jsx
const string = "Javascript is a programming language."
const newArr = string.split(" ");
console.log(newArr);
```

If you noticed in the above code, I add space inside the .split method.

This space is used as a separator to split a string into an array of substrings. A split method doesn't change the value of the original string.

If you do `console.log(newArr)`. You'll get a new array that looks like this.

```jsx
["Javascript", "is", "a", "programming", "language."]
```

Now, your string is converted into an array. This method is one of the most powerful method.
 
2.
 **Math.random:**

This method returns a random number between 0 (inclusive) and 1 (exclusive).

It basically returns a random floating-point number(decimal number). 

```jsx
const randomNum = Math.random();
console.log(randomNum);
```

If you run the above code, you see a number between 0 and 1 like `0.4795164735135027`.

If you want an integer instead of a floating-point number, you should wrap `Math.random()` with `Math.floor()`. `Math.floor()` method round a number downward to its nearest integer like so.

```jsx
const randomNum = Math.floor(Math.random());
console.log(randomNum);
```

Now, if you want an integer between 0 and 20. Your code should look like this.

```jsx
const number = 20;
const randomNum = Math.floor(Math.random()*number);
console.log(randomNum);
```
I hope you'll understand how `Math.random()` method works.
Now, let's move to our third method.

3.
 **forEach:**

This method is used to loop through an array. If you used `for loop` to loop through an array, after reading this, you'll never go to use that.

let say we have an array:

```jsx
const numbers = [1,2,3,4,5];
```

Now, if you want to multiply each number inside an array by 2, How do you do that?

Here, the `forEach()` method comes into play. Let see how it works.

Basically, the `forEach()` method calls a function once for each element in an array, in order.

```jsx
const numbers = [1,2,3,4,5];
numbers.forEach(number => {
	console.log(number*2);
});

//2
//4
//6
//8
//10 
```

So, in the above code for each number in an array, we call a function which multiplies each number by 2. I think, now you understand how to use `forEach` method.

4.
 **filter():**

The `filter()` method creates a new array with all elements that pass the test implemented by the provided function.

Now, let's take one example to clearly understand it.

```jsx
const ages = [18,15,10,20,22];
const filterArr = ages.filter(age => age>18);
console.log(filterArr);
```

So, in the above example, I take an array of ages and apply the filter method to it.

Filter method executes a function for each element in an array and checks whether it is satisfying the condition provided by the given function or not. If it satisfies the given condition, it returns that element to the new array otherwise it doesn't store that element in the `filterArr` array.

I hope now you have a clear understanding of how to use the filter method. This method is basically used to implement delete functionality in various apps

Note: `filter()` method does not change the value of the original array.

`filter()` method does not run the function for array elements without values.

5.
 **Map method:-**

This method calls a provided function for each element in an array and then it creates a new array with the results of calling a function for every array element.

Now, let's take an example to understand it better.

```jsx
const numbers = [1,2,3,4,5];
const newArr = numbers.map(number => {
	return number*number;
});
console.log(newArr);
```

In the above code, I take a `numbers` array and then apply the `.map` method to it. For each number, I call a function that returns a square of that number and creates a new array named `newArr`

Now, if you do `console.log(newArr)`. You will get a new array that contains a square of numbers like this.

```jsx
[1, 4, 9, 16, 25]
```

This method doesn't change the value of the original array.

**Summary:-**

Now, We have covered 5 of the most powerful javascript methods. These methods are very useful and help us to write cleaner code.

# Thanks for reading this blog

If you find the blog helpful, feel free to subscribe to our newsletter so whenever our post goes live, you'll get the notification first.
 
Do leave your feedback and suggestions as comments.

[Check out my youtube channel](https://bit.ly/2F1aZIh)

[Let's connect on Twitter](https://twitter.com/thefierycoder)