Manipulate array indexes in JavaScript using Array prototype methods

Question

Manipulate array indexes in JavaScript using Array prototype methods

I'm working with an array of users and trying to filter out the admins by finding their indices in the array, but I'm running into some issues. Here's my code:

var users = [
  {name: "Jeff", IsAdmin: false},
  {name: "Jonah", IsAdmin: true},
  {name: "Jonathan", IsAdmin: true}
];

var admins = users.findIndex(function (user) {
     user.IsAdmin == true;
});

var regularUsers = users.filter(function (value, index) {
    return admins.indexOf(index) == -1;
});

Unfortunately, this routine is not working as expected. The admins variable returns null and the filter function is malfunctioning.

Is there a simpler way to accomplish this task?

javascript arrays

Answer 1

Answer №1

To narrow down results, simply filter based on the IsAdmin attribute.

Avoid unnecessary comparisons to true or false when dealing with boolean values. Instead, incorporate the direct attribute within your condition:

//No need for '== true' as IsAdmin is already a boolean attribute.
return user.IsAdmin

//Simply utilize the attribute directly.
return user.IsAdmin

var users = [
  {name: "Jeff", IsAdmin: false},
  {name: "Jonah", IsAdmin: true},
  {name: "Jonathan", IsAdmin: true}
];

var admins = users.findIndex(function (user) {
     return !user.IsAdmin;
});
console.log(admins);

var regularUsers = users.filter(function (user) {
    return !user.IsAdmin;
});

console.log(regularUsers);

Answer 2

To narrow down results, simply filter based on the IsAdmin attribute.

Avoid unnecessary comparisons to true or false when dealing with boolean values. Instead, incorporate the direct attribute within your condition:

//No need for '== true' as IsAdmin is already a boolean attribute.
return user.IsAdmin

//Simply utilize the attribute directly.
return user.IsAdmin

var users = [
  {name: "Jeff", IsAdmin: false},
  {name: "Jonah", IsAdmin: true},
  {name: "Jonathan", IsAdmin: true}
];

var admins = users.findIndex(function (user) {
     return !user.IsAdmin;
});
console.log(admins);

var regularUsers = users.filter(function (user) {
    return !user.IsAdmin;
});

console.log(regularUsers);

Answer 3

Answer №2

const nonAdminUsers = users.filter(user => {
    return !user.isAdmin;
});

In the filtering process, the user will be included in the list if the condition returns true.

Answer 4

const nonAdminUsers = users.filter(user => {
    return !user.isAdmin;
});

In the filtering process, the user will be included in the list if the condition returns true.

Answer 5

Answer №3

findIndex only returns a single index, rather than an array of indices. It's best to avoid filtering by index as it can be quite inefficient - instead, filter directly using the predicate:

const admins = users.filter(user => user.isAdmin);
const regularUsers = users.filter(user => !user.isAdmin);

Answer 6

findIndex only returns a single index, rather than an array of indices. It's best to avoid filtering by index as it can be quite inefficient - instead, filter directly using the predicate:

const admins = users.filter(user => user.isAdmin);
const regularUsers = users.filter(user => !user.isAdmin);

Manipulate array indexes in JavaScript using Array prototype methods

Answer №1

Answer №2

Answer №3

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