Javascript Articles - Page 256 of 534

Suppose we have a two-dimensional array of numbers like this −const arr = [    [1, 3, 2],    [5, 2, 1, 4],    [2, 1] ];We are required to write a JavaScript function that groups all the identical numbers into their own separate subarray, and then the function should sort the group array to place the subarrays into increasing order.Therefore, finally the new array should look like −const output = [    [1, 1, 1],    [2, 2, 2],    [4], [3],    [5] ];ExampleThe code for this will be −const arr = [    [1, 3, 2],   ... Read More

We are required to write a JavaScript function that takes in a string as the first argument and an array of numbers. Our function should replace all the characters in the string at indices that are specified by the array elements taken as the second argument with an asterisk.ExampleThe code for this will be −const str = "Lorem ipsum dolor sit amet consectetur adipiscing elit"; const arr = [4, 7, 9, 12, 15]; const replceWithAsterisk = (str, indices) => {    let res = '';    res = indices.reduce((acc, val) => {       acc[val] = '*';     ... Read More

Suppose, we have a JSON object like this −const obj = {    a: {       someKey: {          propOne: '',          enabled: true       }    },    b: {       someKey: {          propOne: '',          enabled: false       }    },    c: {       someKey: {          propOne: '',          enabled: false       }    },    someKey: {       ab: {     ... Read More

Suppose, we array of arrays like this −const arr = [    [-73.9280684530257, 40.8099975343718],    [-73.9282820374729, 40.8100875554645],    [-73.9280124002104, 40.8103130893677],    [-73.927875543761, 40.8102554080229],    [-73.9280684530257, 40.8099975343718] ];Here each subarray represents a point on a 2-D plane, and each point is a vertex of n sided polygon where n is the number of subarrays in the input arrays.We are required to write a JavaScript function that takes in one such array and returns a new array of n subarrays, each representing the midpoint of corresponding sides of the polygon.ExampleThe code for this will be −const arr = [    [-73.9280684530257, 40.8099975343718],    [-73.9282820374729, 40.8100875554645],    [-73.9280124002104, 40.8103130893677],    [-73.927875543761, 40.8102554080229],    [-73.9280684530257, 40.8099975343718] ]; const findCenters = arr => {    const centerArray = [];    for(i = 0; i

Suppose we have two arrays, the first array contains the scheduled date for some events and the second array contains the names of those events, like this −const dates = [    {       id:"1",       date:"2017-11-07"    },    {       id:"1",       date:"2017-11-08"    },    {       id:"2",       date:"2017-11-07"    },    {       id:"2",       date:"2017-11-08"    } ]; const names = [    {       id:"1",       name:"Pervies, Peter"    },    {   ... Read More

Suppose we have an array of arrays like this −const arr = [    [       "Serta",       "Black Friday"    ],    [       "Serta",       "Black Friday"    ],    [       "Simmons",       "Black Friday"    ],    [       "Simmons",       "Black Friday"    ],    [       "Simmons",       "Black Friday"    ],    [       "Simmons",       "Black Friday"    ] ];We are required to write a JavaScript function that ... Read More

Suppose we have two arrays of literals like these −const arr1 = [1, 3, 2, 4, 5, 6]; const arr2 = [1, 2, 5];We are required to write a JavaScript function that takes in two such arrays. Then our function should return a new array that contains all the elements of arr1 but sorted according to arr2.Like the elements that appear in both the array should appear first according to their order in the second array followed by the elements only present in first array retaining their order.ExampleThe code for this will be −const arr1 = [1, 3, 2, 4, ... Read More

Suppose, we have an array of objects like this −const arr = [    {"title": "Assistant"},    {"month": "July"},    {"event": "Holiday"},    {"title": "Assistant"} ];We are required to write a JavaScript function that takes in one such array. Our function should then return a new array that contains all the object from the original array but the duplicate ones.ExampleThe code for this will be −const arr = [    {"title": "Assistant"},    {"month": "July"},    {"event": "Holiday"},    {"title": "Assistant"} ]; const removeDuplicate = arr => {    const map = {};    for(let i = 0; i < ... Read More

We are required to write a JavaScript function that takes in two. Our function should then return a new array that contains characters alternatively from both the strings.For example: If the two strings are −const str1 = 'abc'; const str2 = 'def';OutputThen the output should be −const output = 'adbecf';ExampleThe code for this will be −const str1 = 'abc'; const str2 = 'def'; const mergeAlternatively = (str1, str2) => {    const a = str1.split("").filter(el => !!el);    const b = str2.split("");    let mergedString = '';    for(var i = 0; i < a.length || i < b.length; i++){ ... Read More

We are required to write a JavaScript function that takes in a two-dimensional array of literals.Our function should return a new array that contains all the entries from the original array but the repeating ones.ExampleThe code for this will be −const arr = [    [1,2,3,4,5],    [3,4,6,7,8,2],    [7,2,4,9,11,15],    [10,12,3,7,11] ]; const removeDuplicates = arr => {    let map = {};    let res = [];    res = arr.map(el => {       return el.filter(val => {          if(map[val]){             return false;          };          map[val] = 1;          return true;       });    });    return res; }; console.log(removeDuplicates(arr));OutputThe output in the console −[ [ 1, 2, 3, 4, 5 ], [ 6, 7, 8 ], [ 9, 11, 15 ], [ 10, 12 ] ]