用相同的值更新数组中的所有元素

Question

I have an array of users and want to set age = 0 if there´s no age present

const [users, setUsers] = useState([{name: 'john', age: 40}, {name: 'mary'}, {name: 'mike'}])

how can I do this? (I don´t have access to the database to set all users age to 0 if there´s no age set)

Answer 1

You should do:

setUsers(users.map(user => ({...user, age: user.age || 0})))

Answer 2

I think this is will help.

const users = [{name: 'john', age: 40}, {name: 'mary'}, {name: 'mike'}]
users.map(user => {
  if (user.age === undefined) user.age = 0;
  return user;
});

setUsers(users);