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Javascript Articles
Page 25 of 534
Counting number of 9s encountered while counting up to n in JavaScript
ProblemWe are required to write a JavaScript function that takes in a number n. Our function should count and return the number of times we will have to use 9 while counting from 0 to n.ExampleFollowing is the code −const num = 100; const countNine = (num = 0) => { const countChar = (str = '', char = '') => { return str .split('') .reduce((acc, val) => { if(val === char){ acc++; }; return acc; }, 0); }; let count = 0; for(let i = 0; i
Read MoreAdding and searching for words in custom Data Structure in JavaScript
ProblemWe are required to design a data structure in JavaScript that supports the following two operations −addWord, which adds a word to that Data Structure (DS), we can take help of existing DS like arrays or any other DS to store this data, search, which searches a literal word or a regular expression string containing lowercase letters "a-z" or "." where "." can represent any letterFor exampleaddWord("sir") addWord("car") addWord("mad") search("hell") === false search(".ad") === true search("s..") === trueExampleFollowing is the code −class MyData{ constructor(){ this.arr = []; }; }; MyData.prototype.addWord = function (word) { ...
Read MoreLongest possible string built from two strings in JavaScript
ProblemWe are required to write a JavaScript function that takes in two strings s1 and s2 including only letters from ato z.Our function should return a new sorted string, the longest possible, containing distinct letters - each taken only once - coming from s1 or s2.ExampleFollowing is the code −const str1 = "xyaabbbccccdefww"; const str2 = "xxxxyyyyabklmopq"; const longestPossible = (str1 = '', str2 = '') => { const combined = str1.concat(str2); const lower = combined.toLowerCase(); const split =lower.split(''); const sorted = split.sort(); const res = []; for(const el of sorted){ ...
Read MoreFinding life path number based on a date of birth in JavaScript
Life Path NumberA person's Life Path Number is calculated by adding each individual number in that person's date of birth, until it is reduced to a single digit number.ProblemWe are required to write a JavaScript function that takes in a date in “yyyy-mm-dd” format and returns the life path number for that date of birth.For instance, if the date is: 1999-06-10year : 1 + 9 + 9 + 9 = 28 → 2 + 8 = 10 → 1 + 0 = 1 month : 0 + 6 = 6 day : 1 + 0 = 1 result: 1 + ...
Read MoreSmallest number formed by shuffling one digit at most in JavaScript
ProblemWe are required to write a JavaScript function that takes in a positive number n. We can do at most one operation −Choosing the index of a digit in the number, remove this digit at that index and insert it back to another or at the same place in the number in order to find the smallest number we can get.Our function should return this smallest number.ExampleFollowing is the code −const num = 354166; const smallestShuffle = (num) => { const arr = String(num).split(''); const { ind } = arr.reduce((acc, val, index) => { let ...
Read MoreReturning the value of (count of positive / sum of negatives) for an array in JavaScript
ProblemWe are required to write a JavaScript function that takes in an array of integers (positives and negatives) and our function should return an array, where the first element is the count of positives numbers and the second element is sum of negative numbers.ExampleFollowing is the code −const arr = [1, 2, 1, -2, -4, 2, -6, 2, -4, 9]; const posNeg = (arr = []) => { const creds = arr.reduce((acc, val) => { let [count, sum] = acc; if(val > 0){ count++; }else if(val < 0){ sum += val; }; return [count, sum]; }, [0, 0]); return creds; }; console.log(posNeg(arr));Output[ 6, -16 ]
Read MoreChecking if a string contains all unique characters using JavaScript
ProblemWe are required to write a JavaScript function that takes in a sting and returns true if all the characters in the string appear only once and false otherwise.ExampleFollowing is the code −const str = 'thisconaluqe'; const allUnique = (str = '') => { for(let i = 0; i < str.length; i++){ const el = str[i]; if(str.indexOf(el) !== str.lastIndexOf(el)){ return false; }; }; return true; }; console.log(allUnique(str));Outputtrue
Read MoreValidating a boggle word using JavaScript
ProblemA Boggle board is a 2D array of individual characters, e.g. −const board = [ ["I", "L", "A", "W"], ["B", "N", "G", "E"], ["I", "U", "A", "O"], ["A", "S", "R", "L"] ];We are required to write a JavaScript function that takes in boggle board and a string and checks whether that string is a valid guess in the boggle board or not. Valid guesses are strings which can be formed by connecting adjacent cells (horizontally, vertically, or diagonally) without reusing any previously used cells.For example, in the above board "LINGO", and "ILNBIA" would all be valid ...
Read MoreIs the reversed number a prime number in JavaScript
ProblemWe are required to write a JavaScript function that takes in a number and return true if the reverse of that number is a prime number, false otherwise.ExampleFollowing is the code −const num = 13; const findReverse = (num) => { return +num .toString() .split('') .reverse() .join(''); }; const isPrime = (num) => { let sqrtnum = Math.floor(Math.sqrt(num)); let prime = num !== 1; for(let i = 2; i < sqrtnum + 1; i++){ if(num % i === 0){ prime = false; break; }; }; return prime; } const isReversePrime = num => isPrime(findReverse(num)); console.log(isReversePrime(num));Outputtrue
Read MoreFinding the longest non-negative sum sequence using JavaScript
ProblemWe are required to write a JavaScript function that takes in an array containing a sequence of integers, each element of which contains a possible value ranging between -1 and 1.Our function should return the size of the longest sub-section of that sequence with a sum of zero or higher.ExampleFollowing is the code −const arr = [-1, -1, 0, 1, 1, -1, -1, -1]; const longestPositiveSum = (arr = []) => { let sum = 0; let maxslice = 0; let length = arr.length; const sumindex = []; let marker = length * 2 + ...
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