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Javascript Articles
Page 360 of 534
Picking out uniques from an array in JavaScript
Suppose we have an array that contains duplicate elements like this −const arr = [1, 1, 2, 2, 3, 4, 4, 5];We are required to write a JavaScript function that takes in one such array and returns a new array. The array should only contain the elements that only appear once in the original array.Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [1, 1, 2, 2, 3, 4, 4, 5]; const extractUnique = arr => { const res = []; for(let i = 0; i < arr.length; i++){ ...
Read MoreNon-composite numbers sum in an array in JavaScript
We are required to write a JavaScript function that takes in an array of numbers.The function should return the sum of all the prime numbers present in the array.Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [43, 6, 6, 5, 54, 81, 71, 56, 8, 877, 4, 4]; const isPrime = n => { if (n===1){ return false; }else if(n === 2){ return true; }else{ for(let x = 2; x < n; x++){ if(n % ...
Read MoreInverting slashes in a string in JavaScript
We are required to write a JavaScript function that takes in a string that may contain some backward slashes.And the function should return a new string where all the backslashes with forward slashes.Therefore, let’s write the code for this function −ExampleThe code for this will be −const str = 'Th/s str/ng /conta/ns some/ forward slas/hes'; const invertSlashes = str => { let res = ''; for(let i = 0; i < str.length; i++){ if(str[i] !== '/'){ res += str[i]; continue; }; ...
Read MorePushing false objects to bottom in JavaScript
Suppose we have an array of objects like this −const array = [ {key: 'a', value: false}, {key: 'a', value: 100}, {key: 'a', value: null}, {key: 'a', value: 23} ];We are required to write a JavaScript function that takes in one such array and places all the objects that have falsy values for the "value" property to the bottom and sorts all other objects in decreasing order by the "value" property.Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [ {key: 'a', value: false}, {key: 'a', ...
Read MoreFinding upper elements in array in JavaScript
We are required to write a JavaScript function that takes in an array of numbers as the first argument and a single number as the second argument. The function should return an array of all the elements from the input array that are greater than or equal to the number taken as the second argument.Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr = [56, 34, 2, 7, 76, 4, 45, 3, 3, 34, 23, 2, 56, 5]; const threshold = 40; const findGreater = (arr, num) => { const res = ...
Read MoreSort the second array according to the elements of the first array in JavaScript
Suppose, we have two arrays like these −const arr1 = ['d', 'a', 'b', 'c'] ; const arr2 = [{a:1}, {c:3}, {d:4}, {b:2}];We are required to write a JavaScript function that accepts these two arrays. The function should sort the second array according to the elements of the first array.We have to sort the keys of the second array according to the elements of the first array.Therefore, the output should look like −const output = [{d:4}, {a:1}, {b:2}, {c:3}];Therefore, let’s write the code for this function −ExampleThe code for this will be −const arr1 = ['d', 'a', 'b', 'c'] ; const ...
Read MoreAbsolute difference of Number arrays in JavaScript
Suppose, we have two arrays like these −const arr1 = [1, 2, 3, 4, 5, 6]; const arr2 = [9, 8, 7, 5, 8, 3];We are required to write a JavaScript function that takes in such two arrays and returns an array of absolute difference between the corresponding elements of the array.So, for these arrays, the output should look like −const output = [8, 6, 4, 1, 3, 3];We will use a for loop and keep pushing the absolute difference iteratively into a new array and finally return the array.Therefore, let’s write the code for this function −ExampleThe code for ...
Read MoreConstructing an object from repetitive numeral string in JavaScript
Suppose, we have a string with digits like this −const str = '11222233344444445666';We are required to write a JavaScript function that takes in this string and returns an object that represents the count of each number in the string.So, for this string, the output should be −const output = { "1": 2, "2": 4, "3": 3, "4": 7, "5": 1, "6": 3 };Therefore, let’s write the code for this function −ExampleThe code for this will be −const str = '11222233344444445666'; const mapString = str => { const map = {}; for(let i ...
Read MoreSumming up unique array values in JavaScript
We are required to write a JavaScript function that takes in an array of numbers that may contain some duplicate numbers. Our function should return the sum of all the unique elements (elements that only appear once in the array) present in the array.For exampleIf the input array is −const arr = [2, 5, 5, 3, 2, 7, 4, 9, 9, 11];Then the output should be 25.We will simply use a for loop, iterate the array and return the sum of unique elements.ExampleThe code for this will be −const arr = [2, 5, 5, 3, 2, 7, 4, 9, 9, ...
Read MoreAdd matching object values in JavaScript
Suppose, we have an array of objects like this −const arr = [{a: 2, b: 5, c: 6}, {a:3, b: 4, d:1}, {a: 1, d: 2}];Each object is bound to have unique in itself (for it to be a valid object), but two different objects can have the common keys (for the purpose of this question).We are required to write a JavaScript function that takes in one such array and returns an object with all the unique keys present in the array and their values cumulative sum as the value.So, the resultant object should look like −const output = {a: ...
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