Higher Order Array Functions | Map, Filter, Reduce | JavaScript ES6 Tutorial

In this video, we will learn about the higher-order functions in javascript like map, filter, and reduce.

#javascript

What is GEEK

Buddha Community

Definitive Guide to Understand Javascript Array reduce()

Javascript array reduce() is an inbuilt method that is used to apply a function to each element in the array to reduce the array to a single value. The reduce() function executes the provided function for each value of an array from left-to-right. The return value of a function is stored in an accumulator.

Understanding Javascript array reduce()

JavaScript array reduce() is one of the pioneer function of functional programming. The reduce() method accepts two parameters, the total and the current value. If you want to add all the values of an array, then use the array reduce() function.

It is similar to both  Javascript map() and  Javascript filter() but, it differs in the callback arguments.

The callback now receives an accumulator (it accumulates all the return values. Its value is the accumulation of a previously returned accumulations), a current value, a current index, and finally, the whole array.

#javascript #javascript map #javascript filter #javascript array reduce

JavaScript Arrays Tutorial. DO NOT MISS!!!

Learn JavaScript Arrays

📺 The video in this post was made by Programming with Mosh
The origin of the article: https://www.youtube.com/watch?v=oigfaZ5ApsM&list=PLTjRvDozrdlxEIuOBZkMAK5uiqp8rHUax&index=4
🔥 If you’re a beginner. I believe the article below will be useful to you ☞ What You Should Know Before Investing in Cryptocurrency - For Beginner
⭐ ⭐ ⭐The project is of interest to the community. Join to Get free ‘GEEK coin’ (GEEKCASH coin)!
☞ **-----CLICK HERE-----**⭐ ⭐ ⭐
Thanks for visiting and watching! Please don’t forget to leave a like, comment and share!

#arrays #javascript #javascript arrays #javascript arrays tutorial

Higher-Order Functions Beginners Should Be Familiar With.

Higher-order functions are functions that operate on other functions, either by taking them as arguments or by returning them.

There are a lot more higher order functions than what will be covered in this article, but these are good ones to get you up and running as a beginner. These standard array methods are forEach() , filter() , map() and sort() .

1. **forEach( ): **This is used when you want to operate on or interact with any element inside of an array. Basically works like the_ for loop._

N.B- I’d be using examples to illustrate each method so you can get a clearer picture, and also just printing to the console to keep the examples as simple and basic as possible.

Example: Lets say in an array of a group or friends, and we want to loop through that array and print to the console each element of that array.

Using a for loop ;

const friends = ['Toyin', 'Olumide', 'Fola', 'Tola'];

for ( let i=0; i < friends.length ; i++) {
  cosole.log (friends[i])
};

The action same as above can be achieved using theforEach() method as seen below;

const friends =  ['Toyin', 'Olumide', 'Fola', 'Tola'];

friends.forEach(function(name) {
  console.log(name)
};

What the forEach() method simply does is to take in a function as an argument and loop through each item in the array without using iteration[i].

This is really awesome when the ES6 arrow functions are used, our code is reduced to a single line that is clean and maintainable. As seen below:

const friends =  ['Toyin', 'Olumide', 'Fola', 'Tola'];

friends.forEach(name => console.log (name));

2. **_filter( ) : _**Just like the name implies, it is used to filter out elements of an array that do not meet the conditions set in the callback function passed as an argument. The callback function passed to the filter() method accepts 3 parameters: element, index, and array , but most times only the element parameter is used.

**Example : **In an array showing a group of friends and their ages, lets say we want to print to the console the friends that can drink assuming the age limit for drinking is 18. Using a for loop without high order functions;

const friends = [
  {name : 'Toyin', age: 24},
  {name : 'Olumide', age: 14},
  {name : 'Fola', age: 12},
  {name : 'David', age: 42}
];
for ( let i=0 ; i<friends.length ; i++) {
   if (friends[i].age > 18) {
    console.log(`${friends[i].name} can drink`);
 }
};

Now using the filter() method :

const friends = [
  {name : 'Toyin', age: 24},
  {name : 'Olumide', age: 14},
  {name : 'Fola', age: 12},
  {name : 'David', age: 42}
];
friends.filter (function (friend) {
  if (friend.age > 18){
   return true;
 } 
});

#functional-programming #beginners-guide #javascript #higher-order-function #es5-vs-es6 #function

map(), filter() and reduce() in JavaScript.

**_map, filter and reduce _**are essentially just some of the most well-known, easy to use, higher-order functions that run provided callback on each element of an array.

In this article, we will explore how using map(), filter(), and reduce() can help make our code:

**1.**Easy to comprehend.

2. Less prone to side effects as these function don’t modify the actual array, and instead create a new one.

**3. **Avoid explicit loops.

Let’s explore and familiarize ourselves with these functions.

#functional-programming #filters #maps #javascript #reduce

Array Foreach, Map, Filter, Reduce, Concat Methods in Javascript

In this tutorial, we will see Javascript Array Foreach, Map, Filter, Reduce, Concat Methods. I dedicate this article only for these methods because, in Pure Functional Programming, this kind of method is required to perform some operations on an Array.

If you do not know What Pure Functions is, then check out my Pure Functions in Javascript article on this website.

Arrays

All the programming languages have this kind of Data Structure to hold and manipulate the data and Javascript is not different.

We all know Arrayscollection of variables, and we all have used to perform some operations like Creating an array, Removing an Item from an Array, Sorting the data of an Array and other manipulations.

In Functional Programming, we are using functions like foreach, map, filter, reduce, concatAll and other Higher Order Functions. So today I am describing these functions in deep and show you how you can use it in various scenarios.

#javascript #programming #foreach #map #filter #reduce