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Javascript Articles
Page 308 of 534
Counting smaller and greater in JavaScript
Suppose, we have an array of literals like this −const arr = [3, 5, 5, 2, 23, 4, 7, 8, 8, 9];We are required to write a JavaScript function that takes in this array and a number, say n, and returns an object representing the count of elements greater than and smaller than n.Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [3, 5, 5, 2, 23, 4, 7, 8, 8, 9]; const smallerLargerNumbers = (arr, num) => { return arr.reduce((acc, val) => { let { greater, smaller ...
Read MoreUsing one array to help filter the other in JavaScript
Suppose, we have an array and objects like these −Objects:const main = [ {name: "Karan", age: 34}, {name: "Aayush", age: 24}, {name: "Ameesh", age: 23}, {name: "Joy", age: 33}, {name: "Siddarth", age: 43}, {name: "Nakul", age: 31}, {name: "Anmol", age: 21}, ];Array:const names = ["Karan", "Joy", "Siddarth", "Ameesh"];We are required to write a JavaScript function that takes in two such arrays and filters the first array in place to contain only those objects whose name property is included in the second array.Therefore, let’s write the code for this function −ExampleThe code for this ...
Read MoreMapping string to Numerals in JavaScript
We are required to write a JavaScript function that takes in a string. It should print out each number for every corresponding letter in the string.For example:a = 1 b = 2 c = 3 d = 4 e =5 . . . y = 25 z = 25Note: Remove any special characters and spaces.So, if the input is −"hello man"Then the output should be −"8, 5, 12, 12, 15, 13, 1, 14"ExampleThe code for this will be −const str = 'hello man'; const charPosition = str => { str = str.split(''); const arr = []; const ...
Read MoreFinding the smallest fitting number in JavaScript
We are required to write a JavaScript function that takes in an array of numbers and returns a number which can exactly divide all the numbers in the array.Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [4, 6, 34, 76, 78, 44, 34, 26, 88, 76, 42]; const dividesAll = el => { const result = []; let num; for (num = Math.floor(el / 2); num > 1; num--){ if (el % num === 0) { result.push(num); } }; return result; }; const dividesArray = arr => { return arr.map(dividesAll).reduce((acc, val) => { return acc.filter(el => val.includes(el)); }); }; console.log(dividesArray(arr));OutputThe output in the console will be −[ 2 ]
Read MoreSorting Array without using sort() in JavaScript
We are required to write a JavaScript function that takes in an array of numbers.The function should sort the array using the Array.prototype.sort() method, but, here, we are required to use the Array.prototype.reduce() method to sort the array.Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [4, 56, 5, 3, 34, 37, 89, 57, 98]; const sortWithReduce = arr => { return arr.reduce((acc, val) => { let ind = 0; while(ind < arr.length && val < arr[ind]){ ind++; } acc.splice(ind, 0, val); return acc; }, []); }; console.log(sortWithReduce(arr));OutputThe output in the console will be −[ 98, 57, 89, 37, 34, 5, 56, 4, 3 ]
Read MoreSquared concatenation of a Number in JavaScript
We are required to write a JavaScript function that takes in a number and returns a new number in which all the digits of the original number are squared and concatenated.For example: If the number is −99Then the output should be −8181because 9^2 is 81 and 1^2 is 1.Therefore, let’s write the code for this function −ExampleThe code for this will be −const num = 9119; const squared = num => { const numStr = String(num); let res = ''; for(let i = 0; i < numStr.length; i++){ const square = Math.pow(+numStr[i], 2); ...
Read MoreRepeated sum of Number’s digits in JavaScript
We are required to write a JavaScript function that recursively sums up the digits of a number until it reduces to a single digit number.We are required to do so without converting the number to String or any other data type.Therefore, let’s write the code for this function −ExampleThe code for this will be −const num = 546767643; const sumDigit = (num, sum = 0) => { if(num){ return sumDigit(Math.floor(num / 10), sum + (num % 10)); } return sum; }; const sumRepeatedly = num => { while(num > 9){ num = sumDigit(num); }; return num; }; console.log(sumRepeatedly(num));OutputThe output in the console will be −3
Read MoreTaking common elements from many arrays in JavaScript
We are required to write a JavaScript function that takes in any arbitrary number of arrays and returns an array of elements that are common to all arrays. If there are no common elements, then we should return an empty array.Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr1 = [2, 6, 7, 1, 7, 8, 4, 3]; const arr2 = [5, ,7, 2, 2, 1, 3]; const arr3 = [1, 56, 345, 6, 54, 2, 68, 85, 3]; const intersection = (arr1, arr2) => { const res = []; for(let ...
Read MoreSumming up digits and finding nearest prime in JavaScript
We are required to write a JavaScript function that takes in a number, finds the sum of its digits and returns a prime number that is just greater than or equal to the sum.Therefore, let’s write the code for this function −ExampleThe code for this will be −const num = 56563; const digitSum = (num, sum = 0) => { if(num){ return digitSum(Math.floor(num / 10), sum + (num % 10)); } return sum; }; const isPrime = n => { if (n===1){ return false; }else if(n === 2){ ...
Read MoreAdding up identical elements in JavaScript
We are required to write a JavaScript function that takes in an array of Numbers and sums all the identical numbers together at one index.For exampleIf the input array is −const arr = [20, 10, 15, 20, 15, 10];Then the output should be −const output = [40, 20, 30];Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [20, 10, 15, 20, 15, 10]; const addSimilar = arr => { for(let i = 0; i < arr.length; i++){ while(i !== arr.lastIndexOf(arr[i])){ const ind = arr.lastIndexOf(arr[i]); arr[i] += arr.splice(ind, 1)[0]; }; }; }; addSimilar(arr); console.log(arr);OutputThe output in the console will be −[ 40, 20, 30 ]
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