const array1 = ['a', 'b', 'c'];
const array2 = ['d', 'e', 'f'];
const array3 = [...array1, ...array2];
console.log(array3);
// expected output: Array ["a", "b", "c", "d", "e", "f"]var messages = [{userId: 2, content: "Salam"}, {userId: 5, content: "Hello"},{userId: 4, content: "Moi"}];
var users = [{id: 2, name: "Grace"}, {id: 4, name: "Janetta"},{id: 5, name: "Sara"}];
var messagesWithUserNames = messages.map((msg)=> {
var haveEqualId = (user) => user.id === msg.userId
var userWithEqualId= users.find(haveEqualId)
return Object.assign({}, msg, userWithEqualId)
})
console.log(messagesWithUserNames)