A Pronic number is a number which is the product of two consecutive integers, that is, a number of the form n(n + 1).We are required to write a JavaScript function that takes in a number and returns true if it is a Pronic number otherwise returns falseLet’s write the code for this function −Exampleconst num = 90; const isPronic = num => {    let nearestSqrt = Math.floor(Math.sqrt(num)) - 1;    while(nearestSqrt * (nearestSqrt + 1)

We are required to write a JavaScript function that takes in an array of positive as well as negative Numbers and changes the positive numbers to corresponding negative numbers and the negative numbers to corresponding positive numbers in place.Let’s write the code for this function −ExampleFollowing is the code −const arr = [12, 5, 3, -1, 54, -43, -2, 34, -1, 4, -4]; const changeSign = arr => {    arr.forEach((el, ind) => {       arr[ind] *= -1;    }); }; changeSign(arr); console.log(arr);OutputFollowing is the output in the console −[    -12, -5,  -3, 1, -54,    43,  2, -34, 1,  -4,    4 ]

Collinear PointsThree or more points that lie on the same straight line are called collinear points.And three points lie on the same if the slope of all three pairs of lines formed by them is equal.Consider, for example, three arbitrary points A, B and C on a 2-D plane, they will be collinear if −slope of AB = slope of BC = slope of acceptsSlope of a line −The slope of a line is generally given by the tangent of the angle it makes with the positive direction of x-axis.Alternatively, if we have two points that lie on the line, ... Read More

We are required to write a JavaScript function that takes in a string and replaces the adjacent words of that string.For example: If the input string is −const str = "This is a sample string only";Then the output should be −"is This sample a only string"Let’s write the code for this function −ExampleFollowing is the code −const str = "This is a sample string only"; const replaceWords = str => {    return str.split(" ").reduce((acc, val, ind, arr) => {       if(ind % 2 === 1){          return acc;       }     ... Read More

We are required to write a JavaScript function that takes in two numbers, say m and n and returns two numbers whose sum is n and product is m. If there exist no such numbers, then our function should return falseLet’s write the code for this function −Exampleconst perfectNumbers = (sum, prod) => {    for(let i = 0; i < (sum / 2); i++){       if(i * (sum-i) !== prod){          continue;       };       return [i, (sum-i)];    };    return false; }; // 12 12 are not two distinct numbers console.log(perfectNumbers(24, 144)); console.log(perfectNumbers(14, 45)); console.log(perfectNumbers(21, 98));OutputFollowing is the output in the console −false [ 5, 9 ] [ 7, 14 ]

We are required to write a JavaScript function that takes in array of strings and delete every one of the two string that start with the same letter.For example, If the actual array is −const arr = ['Apple', 'Jack' , 'Army', 'Car', 'Jason'];Then, we have to keep only one string in the array, so one of the two strings starting with A should get deleted. In the same way, the logic follows for the letter J in the above array.Let’s write the code for this function −Exampleconst arr = ['Apple', 'Jack' , 'Army', 'Car', 'Jason']; const delelteSameLetterWord = arr => ... Read More

In this article, we will learn to convert an array with a null value to a string in Javascript. Handling arrays containing null, undefined, and falsy values in JavaScript is a frequent challenge. The default methods might not behave as expected when converting such arrays to strings, requiring custom solutions for meaningful string representations. Problem Statement Given an array containing null, undefined, empty strings, and other values, the task is to concatenate its elements into a single string while excluding the unwanted values. Following is our array, with some null and undefined values − Input ["Here", "is", null, "an", undefined, ... Read More

We are required to write a JavaScript function that takes in a negative integer and returns the sum of its digitsFor example −-234 --> -2 + 3 + 4 = 5 -54  --> -5 + 4 = -1Let’s write the code for this function −ExampleFollowing is the code −const num = -4345; const sumNum = num => {    return String(num).split("").reduce((acc, val, ind) => {       if(ind === 0){          return acc;       }       if(ind === 1){          acc -= +val;          return acc;       };       acc += +val;       return acc;    }, 0); }; console.log(sumNum(num));OutputFollowing is the output in the console −8

We are required to write a JavaScript function that takes in an array of numbers with duplicate entries and sums all the duplicate entries to one indexFor example −If the input array is −const input = [1, 3, 1, 3, 5, 7, 5, 4];Then the output should be −const output = [2, 6, 7, 10, 4];ExampleLet’s write the code −const input = [1, 3, 1, 3, 5, 7, 5, 3, 4]; const sumDuplicate = arr => {    const map = arr.reduce((acc, val) => {       if(acc.has(val)){          acc.set(val, acc.get(val) + 1);       }else{          return acc;       }, new Map()); }    return Array.from(map, el => el[0] * el[1]); }; console.log(sumDuplicate(input));OutputFollowing is the output in the console −[ 2, 9, 10, 7, 4 ]

We are required to write a JavaScript function that takes in a number and returns the difference of the sums of the digits at even place and the digits odd placeExampleLet’s write the code −const num = 345336; const evenOddDifference = (num, res = 0, ind = 0) => {    if(num){       if(ind % 2 === 0){          res += num % 10;       }else{          res -= num % 10;       };    };    return Math.abs(res); }; console.log(evenOddDifference(num));OutputFollowing is the output in the console −2