How to filter objects by roles array?

Question

I have an array that contains some objects:

const array = [
            {
                id: 1,
                username: "username1",
                roles: [
                    {
                        id: 1,
                        name: "ROLE_USER"
                    },
                    {
                        id: 8,
                        name: "ROLE_ADMIN"
                    }
                ]
            },
            {
                id: 2,
                username: "username2",
                roles: [
                    {
                        id: 1,
                        name: "ROLE_USER"
                    },
                    {
                        id: 10,
                        name: "ROLE_TESTER"
                    }
                ]
            },
            {
                id: 3,
                username: "username3",
                roles: [
                    {
                        id: 1,
                        name: "ROLE_USER"
                    },
                    {
                        id: 8,
                        name: "ROLE_ADMIN"
                    }
                ]
            }
        ]

Now, how do I filter these objects by role? I wanted to get users with "ROLE_ADMIN" only. I tried doing something like:

const admins = array.filter(user => user.roles.filter(role => role.name === "ROLE_ADMIN"));

and

const admins = array.filter(user => user.roles.map(role => role.name === "ROLE_ADMIN"));

and

const admins = array.map(user => user.roles.filter(role => role.name === "ROLE_ADMIN"));

but none of these worked. Can someone help me?

Answer 1

Try to combine filter with some

According to MDN docs:

The some() method tests whether at least one element in the array passes the test implemented by the provided function. It returns a Boolean value.

Below snippet could help you

const data = [
  {
    id: 1,
    username: 'username1',
    roles: [
      {
        id: 1,
        name: 'ROLE_USER'
      },
      {
        id: 8,
        name: 'ROLE_ADMIN'
      }
    ]
  },
  {
    id: 2,
    username: 'username2',
    roles: [
      {
        id: 1,
        name: 'ROLE_USER'
      },
      {
        id: 10,
        name: 'ROLE_TESTER'
      }
    ]
  },
  {
    id: 3,
    username: 'username3',
    roles: [
      {
        id: 1,
        name: 'ROLE_USER'
      },
      {
        id: 8,
        name: 'ROLE_ADMIN'
      }
    ]
  }
]

const res = data.filter(user =>
  user.roles.some(role => role.name === 'ROLE_ADMIN')
)

console.log(res)

Answer 2

An empty array or object will still be truthy in JavaScript. Add .length > 0 for roles filter (your first option) as below

const admins = array.filter(user => user.roles.filter(role => role.name === "ROLE_ADMIN").length > 0);