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Javascript Articles
Page 333 of 534
Sum of all prime numbers in an array - 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.Let’s say the following is our array −const arr = [43, 6, 6, 5, 54, 81, 71, 56, 8, 877, 4, 4];The function should sum the prime numbers i.e.43 + 5 + 71 + 877 = 996ExampleFollowing is the code −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 ...
Read MoreCheck if a string is sorted in JavaScript
We are required to write a JavaScript function that takes in a string and checks whether it is sorted or not.For example −isSorted('adefgjmxz') // true isSorted('zxmfdba') // true isSorted('dsfdsfva') // falseExampleFollowing is the code −const str = 'abdfhlmxz'; const findDiff = (a, b) => a.charCodeAt(0) - b.charCodeAt(0); const isStringSorted = (str = '') => { if(str.length < 2){ return true; }; let res = '' for(let i = 0; i < str.length-1; i++){ if(findDiff(str[i+1], str[i]) > 0){ res += 'u'; ...
Read MoreSorting an array object by property having falsy value - 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.ExampleFollowing is the code −const arr = [ {key: 'a', value: false}, {key: 'a', value: 100}, {key: 'a', value: null}, {key: 'a', ...
Read MoreCounting occurrences of vowel, consonants - JavaScript
We are required to write a JavaScript function that takes in a string which contains English alphabet, for example −const str = 'This is a sample string, will be used to collect some data';The function should return an object containing the count of vowels and consonants in the string i.e. the output should be −{ vowels: 17, consonants: 29 }ExampleFollowing is the code −const str = 'This is a sample string, will be used to collect some data'; const countAlpha = str => { return str.split('').reduce((acc, val) => { const legend = 'aeiou'; ...
Read MoreGetting equal or greater than number from the list of numbers 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.ExampleFollowing is the code −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 = []; for(let i = 0; i < arr.length; i++){ ...
Read MoreBuilding a Map from 2 arrays of values and keys in JavaScript
Suppose, we have two arrays −const keys = [0, 4, 2, 3, 1]; const values = ["first", "second", "third", "fourth", "fifth"];We are required to write a JavaScript function that takes in the keys and the values array and maps the values to the corresponding keys. The output should be −const map = { 0 => 'first', 4 => 'second', 2 => 'third', 3 => 'fourth', 1 => 'fifth' };ExampleFollowing is the code −const keys = [0, 4, 2, 3, 1]; const values = ["first", "second", "third", "fourth", "fifth"]; const buildMap = (keys, values) => { ...
Read MoreRemove array duplicates by property - JavaScript
Suppose, we have an array of objects like this −const arr = [{name: "Jack", age: "14"}, {name: "bob", age: "14"}, {name: "sue", age: "21"}, {name: "Jill", age: "16"}, {name: "Jack", age: "21"}];We are required to write a JavaScript function that takes in one such array and removes all the objects that have duplicate values for the name.Therefore, for the above array, the output should be −const arr = [{name: "Jack", age: "14"}, {name: "bob", age: "14"}, {name: "sue", age: "21"}, {name: "Jill", age: "16"}];ExampleFollowing is the code −const arr = [ {name: "Jack", age: "14"}, {name: "bob", age: ...
Read MoreJavaScript - Convert an array to key value pair
Suppose we have an array like this −const arr = [ {"name": "Rahul", "score": 89}, {"name": "Vivek", "score": 88}, {"name": "Rakesh", "score": 75}, {"name": "Sourav", "score": 82}, {"name": "Gautam", "score": 91}, {"name": "Sunil", "score": 79}, ];We are required to write a JavaScript function that takes in one such array and constructs an object where name value is the key and the score value is their value.Use the Array.prototype.reduce() method to construct an object from the array.ExampleFollowing is the code −const arr = [ {"name": "Rahul", "score": 89}, {"name": "Vivek", "score": 88}, {"name": ...
Read MoreReturning the highest number from object properties value – JavaScript
Suppose, we have an object that contains rating of a property over some criteria like this −const rating = { "overall": 92, "atmosphere": 93, "cleanliness": 94, "facilities": 89, "staff": 94, "security": 92, "location": 88, "valueForMoney": 92 }We are required to write a JavaScript function that takes in one such object and returns the key value pair that has the highest value.For example, for this very object, the output should be −const output = { "staff": 94 };ExampleFollowing is the code −const rating = { "overall": 92, "atmosphere": 93, ...
Read MoreFind indexes of multiple minimum value in an array in JavaScript
Suppose we have an array of numbers like this −const arr = [1, 2, 3, 4, 1, 7, 8, 9, 1];Suppose we want to find the index of the smallest element in the array i.e. 1 above.For this, we can simply use −const min = Math.min.apply(Math, arr); const ind = arr.indexOf(min);The above code will successfully set ind to 0, which indeed is correct.But what we want to achieve is that if there are more than one minimum elements in the array, like in the above array (three 1s), then we should return an array containing all the indices of minimum ...
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