Test case details

Preparation Code

const arr = [ {firstName:"A", lastName:"Doe", age:1}, {firstName:"B", lastName:"Doe", age:2}, {firstName:"C", lastName:"Doe", age:3}, {firstName:"D", lastName:"Doe", age:4}, {firstName:"E", lastName:"Doe", age:5}, {firstName:"F", lastName:"Doe", age:6}, {firstName:"G", lastName:"Doe", age:6}, {firstName:"H", lastName:"Doe", age:6}, {firstName:"I", lastName:"Doe", age:6}, {firstName:"J", lastName:"Doe", age:6}, {firstName:"K", lastName:"Doe", age:6}, { firstName: "L", lastName: "Doe", age: 7 }, { firstName: "M", lastName: "Doe", age: 8 }, { firstName: "N", lastName: "Doe", age: 9 }, { firstName: "O", lastName: "Doe", age: 10 }, { firstName: "P", lastName: "Doe", age: 11 }, { firstName: "Q", lastName: "Doe", age: 12 }, { firstName: "R", lastName: "Doe", age: 13 }, { firstName: "S", lastName: "Doe", age: 14 }, { firstName: "T", lastName: "Doe", age: 15 }, { firstName: "U", lastName: "Doe", age: 16 }, { firstName: "V", lastName: "Doe", age: 17 }, { firstName: "W", lastName: "Doe", age: 18 }, { firstName: "X", lastName: "Doe", age: 19 }, { firstName: "Y", lastName: "Doe", age: 20 }, { firstName: "Z", lastName: "Doe", age: 21 }, { firstName: "AA", lastName: "Doe", age: 22 }, { firstName: "AB", lastName: "Doe", age: 23 }, { firstName: "AC", lastName: "Doe", age: 24 }, { firstName: "AD", lastName: "Doe", age: 25 }, { firstName: "AE", lastName: "Doe", age: 26 }, { firstName: "AF", lastName: "Doe", age: 27 }, { firstName: "AG", lastName: "Doe", age: 28 }, { firstName: "AH", lastName: "Doe", age: 29 }, { firstName: "AI", lastName: "Doe", age: 30 }, { firstName: "AJ", lastName: "Doe", age: 31 }, { firstName: "AK", lastName: "Doe", age: 32 }, { firstName: "AL", lastName: "Doe", age: 33 }, { firstName: "AM", lastName: "Doe", age: 34 }, { firstName: "AN", lastName: "Doe", age: 35 }, { firstName: "AO", lastName: "Doe", age: 36 }, { firstName: "AP", lastName: "Doe", age: 37 }, { firstName: "AQ", lastName: "Doe", age: 38 }, { firstName: "AR", lastName: "Doe", age: 39 }, { firstName: "AS", lastName: "Doe", age: 40 }, { firstName: "AT", lastName: "Doe", age: 41 }, { firstName: "AU", lastName: "Doe", age: 42 }, { firstName: "AV", lastName: "Doe", age: 43 }, { firstName: "AW", lastName: "Doe", age: 44 }, { firstName: "AX", lastName: "Doe", age: 45 }, { firstName: "AY", lastName: "Doe", age: 46 }, { firstName: "AZ", lastName: "Doe", age: 47 }, { firstName: "BA", lastName: "Doe", age: 48 }, { firstName: "BB", lastName: "Doe", age: 49 }, { firstName: "BC", lastName: "Doe", age: 50 }, { firstName: "BD", lastName: "Doe", age: 51 }, { firstName: "BE", lastName: "Doe", age: 52 }, { firstName: "BF", lastName: "Doe", age: 53 }, { firstName: "BG", lastName: "Doe", age: 54 }, { firstName: "BH", lastName: "Doe", age: 55 }, { firstName: "BI", lastName: "Doe", age: 56 }, { firstName: "BJ", lastName: "Doe", age: 57 }, { firstName: "BK", lastName: "Doe", age: 58 }, { firstName: "BL", lastName: "Doe", age: 59 }, { firstName: "BM", lastName: "Doe", age: 60 }, { firstName: "BN", lastName: "Doe", age: 61 }, { firstName: "BO", lastName: "Doe", age: 62 }, { firstName: "BP", lastName: "Doe", age: 63 }, { firstName: "BQ", lastName: "Doe", age: 64 }, { firstName: "BR", lastName: "Doe", age: 65 }, { firstName: "BS", lastName: "Doe", age: 66 }, { firstName: "BT", lastName: "Doe", age: 67 }, { firstName: "BU", lastName: "Doe", age: 68 }, { firstName: "BV", lastName: "Doe", age: 69 }, { firstName: "BW", lastName: "Doe", age: 70 }, { firstName: "BX", lastName: "Doe", age: 71 }, { firstName: "BY", lastName: "Doe", age: 72 }, { firstName: "BZ", lastName: "Doe", age: 73 }, { firstName: "CA", lastName: "Doe", age: 74 }, { firstName: "CB", lastName: "Doe", age: 75 }, { firstName: "CC", lastName: "Doe", age: 76 }, { firstName: "CD", lastName: "Doe", age: 77 }, { firstName: "CE", lastName: "Doe", age: 78 }, { firstName: "CF", lastName: "Doe", age: 79 }, { firstName: "CG", lastName: "Doe", age: 80 }, { firstName: "CH", lastName: "Doe", age: 81 }, { firstName: "CI", lastName: "Doe", age: 82 }, { firstName: "CJ", lastName: "Doe", age: 83 }, { firstName: "CK", lastName: "Doe", age: 84 }, { firstName: "CL", lastName: "Doe", age: 85 }, { firstName: "CM", lastName: "Doe", age: 86 }, { firstName: "CN", lastName: "Doe", age: 87 }, { firstName: "CO", lastName: "Doe", age: 88 }, { firstName: "CP", lastName: "Doe", age: 89 }, { firstName: "CQ", lastName: "Doe", age: 90 }, ]

Test cases

Test #1

const idMap = new Map; arr.forEach((person) => { const newPerson = { "id": person.firstName }; idMap.set(newPerson.id, person.age); }); arr.forEach((person) => { const test = idMap.get(person.firstName); });

Test #2

const tests = [] arr.forEach((person) => { const newPerson = { "id": person.firstName, "age": person.age }; tests.push(newPerson) }); arr.forEach((person) => { const test = tests.find((el) => el.id === person.firstName) });