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Technical articles with clear explanations and examples

Get the property of the difference between two objects in JavaScript

AmitDiwan
AmitDiwan
Updated on 19-Aug-2020 4K+ Views

Let’s say, we are given two objects that have similar key value pairs with one or key having different values in both objects. Our job is to write a function that takes in the two objects as argument and returns the very first key it finds having different values. If all the keys have exact same values, it should return -1.Here are the sample objects −const obj1 = {    name: 'Rahul Sharma',    id: '12342fe4554ggf',    isEmployed: true,    age: 45,    salary: 190000,    job: 'Full Stack Developer',    employedSince: 2005 } const obj2 = {    name: ...

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How to make a list of partial sums using forEach JavaScript

AmitDiwan
AmitDiwan
Updated on 19-Aug-2020 325 Views

We have an array of numbers like this −const arr = [1, 1, 5, 2, -4, 6, 10];We are required to write a function that returns a new array, of the same size but with each element being the sum of all elements until that point.So, the output should look like −const output = [1, 2, 7, 9, 5, 11, 21];Let’s write the function partialSum(). The full code for this function will be −Exampleconst arr = [1, 1, 5, 2, -4, 6, 10]; const partialSum = (arr) => {    const output = [];    arr.forEach((num, index) => {   ...

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Recursive sum all the digits of a number JavaScript

AmitDiwan
AmitDiwan
Updated on 19-Aug-2020 2K+ Views

Let’s say, we are required to create a function that takes in a number and finds the sum of its digits recursively until the sum is a one-digit number.For example −findSum(12345) = 1+2+3+4+5 = 15 = 1+5 = 6So, the output should be 6.Let’s write the code for this function findSum() −Example// using recursion const findSum = (num) => {    if(num < 10){       return num;    }    const lastDigit = num % 10;    const remainingNum = Math.floor(num / 10);    return findSum(lastDigit + findSum(remainingNum)); } console.log(findSum(2568));We check if the number is less than 10, ...

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How to sum elements at the same index in array of arrays into a single array? JavaScript

AmitDiwan
AmitDiwan
Updated on 19-Aug-2020 1K+ Views

We have an array of arrays and are required to write a function that takes in this array and returns a new array that represents the sum of corresponding elements of original array.If the original array is −[    [43, 2, 21], [1, 2, 4, 54], [5, 84, 2], [11, 5, 3, 1] ]Then the output should be −[60, 93, 30, 55]Let’s write a sample function addArray()The full code for this function will be −Exampleconst arr = [    [43, 2, 21], [1, 2, 4, 54], [5, 84, 2], [11, 5, 3, 1] ]; const sumArray = (array) => { ...

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Converting Odd and Even-indexed characters in a string to uppercase/lowercase in JavaScript?

AmitDiwan
AmitDiwan
Updated on 19-Aug-2020 2K+ Views

We need to write a function that reads a string and converts the odd indexed characters in the string to upperCase and the even ones to lowerCase and returns a new string.Full code for doing the same will be −Exampleconst text = 'Hello world, it is so nice to be alive.'; const changeCase = (str) => {    const newStr = str    .split("")    .map((word, index) => {       if(index % 2 === 0){          return word.toLowerCase();       }else{          return word.toUpperCase();       }    })   ...

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Sort Array of numeric &amp; alphabetical elements (Natural Sort) JavaScript

AmitDiwan
AmitDiwan
Updated on 19-Aug-2020 1K+ Views

We have an array that contains some numbers and some strings. We are required to sort the array such that the numbers gets sorted and get placed before every string and then the string should be placed sorted alphabetically.For example −This array after being sortedconst arr = [1, 'fdf', 'afv', 6, 47, 7, 'svd', 'bdf', 9];Should look like this −[1, 6, 7, 9, 47, 'afv', 'bdf', 'fdf', 'svd']So, let’s write the code for this −Exampleconst arr = [1, 'fdf', 'afv', 6, 47, 7, 'svd', 'bdf', 9]; const sorter = (a, b) => {    if(typeof a === 'number' && typeof ...

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Validate input: replace all &lsquo;a&rsquo; with &lsquo;@&rsquo; and &lsquo;i&rsquo; with &lsquo;!&rsquo;JavaScript

AmitDiwan
AmitDiwan
Updated on 19-Aug-2020 145 Views

We are required to write a function validate() that takes in a string as one and only argument and returns another string that has all ‘a’ and ‘i’ replaced with ‘@’ and ‘!’ respectively.It’s one of those classic for loop problems where we iterate over the string with its index and construct a new string as we move through.The code for the function will be −Exampleconst string = 'Hello, is it raining in Amsterdam?'; const validate = (str) => {    let validatedString = '';    for(let i = 0; i < str.length; i++){       if(str[i] === 'a'){ ...

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Create a polyfill to replace nth occurrence of a string JavaScript

AmitDiwan
AmitDiwan
Updated on 19-Aug-2020 544 Views

Let’s say, we have created a polyfill function removeStr() that takes in three arguments, namely −subStr → the occurrence of which String is to be removednum → it’s a Number (num)th occurrence of subStr is to be removed from stringThe function should return the new if the removal of the subStr from the string was successfully, otherwise it should return -1 in all cases.For example −const str = 'drsfgdrrtdr'; console.log(str.removeStr('dr', 3));Expected output −'drsfgdrrt'Let’s write the code for this −Exampleconst str = 'drsfgdrrtdr'; const subStr = 'dr'; const num = 2; removeStr = function(subStr, num){    if(!this.includes(subStr)){       return ...

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Finding out the Harshad number JavaScript

AmitDiwan
AmitDiwan
Updated on 19-Aug-2020 631 Views

Harshad numbers are those numbers which are exactly divisible by the sum of their digits. Like the number 126, it is completely divisible by 1+2+6 = 9.All single digit numbers are harshad numbers.Harshad numbers often exist in consecutive clusters like [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], [110, 111, 112], [1010, 1011, 1012].Our job is to write a function that takes in a Number as input checks whether it’s a harshad number or not, if not then returns -1 otherwise it returns the length of streak of consecutive harshad cluster.For example −harshadNum(1014) = harshadNum(1015) = harshadNum(1016) = ...

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How to create a random number between a range JavaScript

AmitDiwan
AmitDiwan
Updated on 19-Aug-2020 298 Views

Our job is to create a function, say createRandom, that takes in two argument and returns a pseudorandom number between the range (max exclusive).The code for the function will be −Exampleconst min = 3; const max = 9; const createRandom = (min, max) => {    const diff = max - min;    const random = Math.random();    return Math.floor((random * diff) + min); } console.log(createRandom(min, max));Understanding the code −We take the difference of max and minWe create a random numberThen we multiply the diff and random to produce random number between 0 and diffThen we add min to it ...

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