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Javascript Articles
Page 250 of 534
Creating a binary spiral array of specific size in JavaScript
ProblemWe are required to write a JavaScript function that takes in a number n. Our function should construct and return an array of N * N order (2-D array), in which the 1s take all the spiralling positions starting from [0, 0] and all the 0s take non-spiralling positions.Therefore, for n = 5, the output will look like −[ [ 1, 1, 1, 1, 1 ], [ 0, 0, 0, 0, 1 ], [ 1, 1, 1, 0, 1 ], [ 1, 0, 0, 0, 1 ], [ 1, 1, 1, 1, 1 ] ]ExampleFollowing ...
Read MorePreparing numbers from jumbled number names in JavaScript
ProblemSuppose the following number name string −const str = 'TOWNE';If we rearrange this string, we can find two number names in it 2 (TWO) and 1 (ONE).Therefore, we expect an output of 21We are required to write a JavaScript function that takes in one such string and returns the numbers present in the string.ExampleFollowing is the code − Live Democonst str = 'TOWNE'; const findNumber = (str = '') => { function stringPermutations(str) { const res = []; if (str.length == 1) return [str]; if (str.length == 2) return [str, str[1]+str[0]]; ...
Read MoreSum of all positives present in an array in JavaScript
ProblemWe are required to write a JavaScript function that takes in an array of numbers (positive and negative). Our function should calculate and return the sum of all the positive numbers present in the array.ExampleFollowing is the code − Live Democonst arr = [5, -5, -3, -5, -7, -8, 1, 9]; const sumPositives = (arr = []) => { const isPositive = num => typeof num === 'number' && num > 0; const res = arr.reduce((acc, val) => { if(isPositive(val)){ acc += val; }; return acc; }, 0); return res; }; console.log(sumPositives(arr));OutputFollowing is the console output −15
Read MoreEven index sum in JavaScript
ProblemWe are required to write a JavaScript function that takes in an array of integers. Our function should return the sum of all the integers that have an even index, multiplied by the integer at the last index.const arr = [4, 1, 6, 8, 3, 9];Expected output −const output = 117;ExampleFollowing is the code − Live Democonst arr = [4, 1, 6, 8, 3, 9]; const evenLast = (arr = []) => { if (arr.length === 0) { return 0 } else { const sub = arr.filter((_, index) => index%2===0) const sum = sub.reduce((a,b) => a+b) const posEl = arr[arr.length -1] const res = sum*posEl return res } } console.log(evenLast(arr));OutputFollowing is the console output −117
Read MoreSeparating data type from array into groups in JavaScript
ProblemWe are required to write a JavaScript function that takes in an array of mixed data types. Our function should return an object that contains data type names as key and their value as array of elements of that specific data type present in the array.ExampleFollowing is the code − Live Democonst arr = [1, 'a', [], '4', 5, 34, true, undefined, null]; const groupDataTypes = (arr = []) => { const res = {}; for(let i = 0; i < arr.length; i++){ const el = arr[i]; const type = typeof el; ...
Read MoreMathematics summation function in JavaScript
ProblemWe are required to write a JavaScript function that takes in a number n. Our function should return the sum of all the natural numbers from 1 to n including both 1 and nExampleFollowing is the code − Live Democonst num = 34; const summation = (num = 1) => { let res = 0; for(let i = 1; i
Read MoreCreating all possible unique permutations of a string in JavaScript
ProblemWe are required to write a JavaScript function that takes in a string str. Our function should create all permutations of the input string and remove duplicates, if present. This means, we have to shuffle all letters from the input in all possible orders.ExampleFollowing is the code − Live Democonst str = 'aabb'; const permute = (str = '') => { if (!!str.length && str.length < 2 ){ return str } const arr = []; for (let i = 0; i < str.length; i++){ let char = str[i] ...
Read MoreReturning number with increasing digits. in JavaScript
ProblemWe are required to write a JavaScript function that takes in a number n. Our function should return it with its digits in descending order. Essentially, we should rearrange the digits to create the highest possible number.ExampleFollowing is the code − Live Democonst num = 5423267; const arrangeInDescending = (num = 1) => { const str = String(num); const arr = str.split(''); arr.sort((a, b) => { return +b - +a; }); const newStr = arr.join(''); const res = Number(newStr); return res; }; console.log(arrangeInDescending(num));OutputFollowing is the console output −7654322
Read MoreCurrified function that multiples array elements in JavaScript
ProblemWe are required to write a JavaScript function that takes in an array and returns another function which in turn takes in a number which returns a new array which is the product of corresponding elements of the input array to the first function and the number provided to the second function.ExampleFollowing is the code − Live Democonst arr = [2, 5, 2, 7, 8, 4]; const num = 4; const produceWith = (arr = []) => (num) => { const res = arr.map(el => { return el * num; }); return res; }; console.log(produceWith(arr)(num));OutputFollowing is the console output −[ 8, 20, 8, 28, 32, 16 ]
Read MoreReturning the expanded form of a number in JavaScript
ProblemWe are required to write a JavaScript function that takes in a number and returns a string of the expanded form of the number, indicating the place value of each number.ExampleFollowing is the code − Live Democonst num = 56577; const expandedForm = (num = 0) => { const str = String(num); let res = ''; let multiplier = Math.pow(10, str.length - 1); for(let i = 0; i < str.length; i++){ const el = +str[i]; const next = +str[i + 1]; if(el){ res += (el * multiplier); }; if(next){ res += ' + '; }; multiplier /= 10; }; return res; }; console.log(expandedForm(num));OutputFollowing is the console output −50000 + 6000 + 500 + 70 + 7
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