Array Examples written in JavaScript

Arrays.js

// REMOVE DUPLICATE VALUES
var fruitBasket = ["banana", "apple", "orange", "watermelon", "apple", "orange", "grape", "apple"];

// First method
var uniqueFruits = Array.from(new Set(fruitBasket));
console.log(uniqueFruits);
// (5) ["banana", "apple", "orange", "watermelon", "grape"]


// Second method
var moreUniqueFruits = [ ...new Set(fruitBasket)];
console.log(moreUniqueFruits);
// (5) ["banana", "apple", "orange", "watermelon", "grape"]



// REPLACE A VALUE
var moreFruits = ["banana", "apple", "orange", "watermelon", "apple", "orange", "grape", "apple"];
moreFruits.splice(0, 2, "potato", "tomato");
console.log(moreFruits);
// (8) ["potato", "tomato", "orange", "watermelon", "apple", "orange", "grape", "apple"]



// EMPTY AN ARRAY
var evenMoreFruits = ["banana", "apple", "orange", "watermelon", "apple", "orange", "grape", "apple"];
moreFruits.length = 0;
console.log(evenMoreFruits)
// []



// CONVERT AN ARRAY TO AN OBJECT
var lessFruits = ["banana", "apple", "orange", "watermelon", "grape"];
console.log(lessFruits);
// (5) ["banana", "apple", "orange", "watermelon", "grape"]
var fruitObject = { ...lessFruits };
console.log(fruitObject);
// {0: "banana", 1: "apple", 2: "orange", 3: "watermelon", 4: "grape"}



// FILL ARRAY WITH DATA
var newArray = new Array(10).fill("1");
console.log(newArray);
// (10) ["1", "1", "1", "1", "1", "1", "1", "1", "1", "1"]



// MERGE ARRAYS
var fruits = ["apple", "banana", "orange"];
var meat = ["poultry", "beef", "fish"];
var vegetables = ["potato", "tomato", "cucumber"];

// METHOD I
var food = [...fruits, ...meat, ...vegetables];
console.log(food)
// (9) ["apple", "banana", "orange", "poultry", "beef", "fish", "potato", "tomato", "cucumber"]

// METHOD II
var moreFood = fruits.concat(meat).concat(vegetables);
// (9) ["apple", "banana", "orange", "poultry", "beef", "fish", "potato", "tomato", "cucumber"]



// FIND INTERSECTION OF 2 ARRAYS
var numOne = [0, 2, 4, 6, 8, 8];
var numTwo = [1, 2, 3, 4, 5, 6];
var duplicatedValues = [...new Set(numOne)].filter(item => numTwo.includes(item));
console.log(duplicatedValues);
// (3) [2, 4, 6]



// REMOVE FALSEY VALUES
var mixedArr = [0, "blue", "", NaN, 9, true, undefined, "white", false];
var trueArr = mixedArr.filter(Boolean);
console.log(trueArr);
// (4) [“blue”, 9, true, “white”]



// RANDOM VALUE
var colors = ["blue", "white", "green", "navy", "pink", "purple", "orange", "yellow", "black", "brown"];
var randomColor = colors[(Math.floor(Math.random() * (colors.length)))]
// console.log(randomColor)
// pink
randomColor = colors[(Math.floor(Math.random() * (colors.length)))]
// "navy"
randomColor = colors[(Math.floor(Math.random() * (colors.length)))]
// "pink"
randomColor = colors[(Math.floor(Math.random() * (colors.length)))]
// "brown"



// REVERSING AN ARRAY
var moreColors = ["blue", "white", "green", "navy", "pink", "purple", "orange", "yellow", "black", "brown"];
var reversedColors = moreColors.reverse();
console.log(reversedColors);
// (10) ["brown", "black", "yellow", "orange", "purple", "pink", "navy", "green", "white", "blue"]



// REDUCE EXAMPLE: addition
var nums = [1, 2, 3, 4, 5, 6, 7, 8, 9];
var sum = nums.reduce((x, y) => x + y);
console.log(sum);
// 45