We have an array of Numbers that contains some positive and negative even and odd numbers. We are required to sort the array in ascending order but all the even numbers should appear before any of the odd number and all the odd numbers should appear after all the even numbers and obviously both sorted within.Therefore, for example −If the input array is −const arr = [-2, 3, 6, -12, 9, 2, -4, -11, -8];Then the output should be −[ -12, -8, -4, -2, 2, 6, -11, 3, 9]Therefore, let’s write the code for this sort function −Exampleconst arr = ... Read More

We have to write a function that takes in an object and a string literals array, and it returns the filtered object with the keys that appeared in the array of strings.For example − If the object is {“a”: [], “b”: [], “c”:[], “d”: []} and the array is [“a”, “d”] then the output should be −{“a”: [], “d”:[]}Therefore, let’s write the code for this function, We will iterate over the keys of the object whether it exists in the array, if it does, if shove that key value pair into a new object, otherwise we keep iterating and return ... Read More

We have to write a function that accepts a string and mirrors its alphabet. For example −If the input is ‘abcd’ The output should be ‘zyxw’The function simply takes every character and map to the that is (26 - N) alphabets away from it, where is the 1 based index of that alphabet like 5 for e and 10 for j.We will use the String.prototype.replace() method here, to match all the English alphabets irrespective of their case. The full code for this function will be −Exampleconst str = 'ABCD'; const mirrorString = str => {    const regex = /[A-Za-z]/g; ... Read More

Let’s say, we have an array that contains the score of some players in different sports. The scores are represented like this −const scores = [    {sport: 'cricket', aman: 54, vishal: 65, jay: 43, hardik: 88, karan:23},    {sport: 'soccer', aman: 14, vishal: 75, jay: 41, hardik: 13, karan:73},    {sport: 'hockey', aman: 43, vishal: 35, jay: 53, hardik: 43, karan:29},    {sport: 'volleyball', aman: 76, vishal: 22, jay: 36, hardik: 24, karan:47},    {sport: 'baseball', aman: 87, vishal: 57, jay: 48, hardik: 69, karan:37}, ];We have to write a function that takes in this array and returns a ... Read More

We have an array of objects, which further have nested objects like this −const arr = [{    id: 0, children: [] }, {       id: 1, children: [{       id: 2, children: [] }, {       id: 3, children: [{          id: 4, children: []       }]    }] }];Our job is to write a recursive function, say assignDepth() that takes in this array and assigns depth property to each nested object. Like the object with id 0 will have depth 0, id 1 will have depth 1 ... Read More

A butterfly shuffled array in JavaScript is an array of Numbers that is sorted such that the numbers decrease as we approach the center of array and increase as we approach the end of array. The biggest number is placed at the very first index.Another variation of butterfly shuffled array is where the numbers increase towards the center and decrease towards the end. In this case the smallest number is placed at the very first index.For people who come from a Mathematics background, it’s somewhat relatable to the Guassian distribution.ExampleSuppose we have this array −const arr = [8, 2, 6, ... Read More

each_cons() - RubyThe each_cons() method of enumerable is an inbuilt method in Ruby that iterates for consecutive N elements starting from each element every time. If no block is given, it returns the enumerator.JS equivalent of each_cons()Suppose we have an array of Number literals (JS equivalent of Ruby’s enumerable in this case), the each_cons function is supposed to be an Array function that executes for each element of the array and accepts a number N (N

We have the following data inside a json file data.json −data.json{    "names": [{       "name": "Ramesh",       "readable": true    }, {       "name": "Suresh",       "readable": false    }, {       "name": "Mahesh",       "readable": true    }, {       "name": "Gourav",       "readable": true    }, {       "name": "Mike",       "readable": false    } ] }Our job is to create a function parseData that takes in the path to this file as one and only argument, ... Read More

The idea here is to take two strings as input and return true if a is substring of b or b is sub string of a, otherwise return false.For example −isSubstr(‘hello’, ‘hello world’) // true isSubstr(‘can I use’ , ‘I us’) //true isSubstr(‘can’, ‘no we are’) //falseTherefore, in the function we will check for the longer string, the one with more characters and check if the other is its substring or not.Here is the code for doing so −Exampleconst str1 = 'This is a self-driving car.'; const str2 = '-driving c'; const str3 = '-dreving'; const isSubstr = (first, second) ... Read More

We are required to write a JavaScript function that takes in a binary number as a string and returns its numerical equivalent in base 10. Therefore, let’s write the code for the function.This one is quite simple, we iterate over the string using a for loop and for each passing bit, we double the number with adding the current bit value to it like this −Exampleconst binaryToDecimal = binaryStr => {    let num = 0;    for(let i = 0; i < binaryStr.length; i++){       num *= 2;       num += Number(binaryStr[i]);    };   ... Read More