What method can be used to verify if a username exists within Angular data?

We want to display online users on a webpage by checking if they are currently active. The current code logs all online users in the console, but we need to show this visually on the page.

public isOnline: boolean = false;
...
...
    ngOnInit() {
        this.socket.emit('online', { room: 'global', user: this.user.username });
        this.socket.on('refreshPage', () => {
          this.GetUserData(this.name);
        });
      ...
      ...
    ngAfterViewInit() {
        this.socket.on('usersOnline', data => {
          console.log(data);
        });
      }

The console displays the list of online users. Now, how can we check if a specific user is online or not? We need to replace the console.log with a logic check that verifies if the user exists in the retrieved data:

this.isOnline = /* [write a logic check this.user.username exist in data ] */

Once we determine if a user is online, we can dynamically add a paragraph tag for each user based on their online status like so:

<p class="" *ngIf="isOnline">online</p>

What adjustments should be made to this code snippet?

Answer №1

To determine if a user is online, you can utilize array.some along with a condition that outputs a boolean true or false.

this.isUserOnline = data.some(d=>d.username == user.username);

Answer №2

Check out this handy code snippet:

var names = ['Javid', 'David', 'Alex', 'John'];
const searchName = "Javid";

function findNameInArray(names){
  return names.filter(item => searchName === item).length ? true : false;
}

console.log(findNameInArray(names));

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