What causes the "Cannot find name" error in this Angular 11 application?

Question

I am working on an Angular 11 application.

In the service UserService I have:

import { Injectable, OnDestroy } from '@angular/core';
import { UserModel } from '../path/to/UserModel';

export class UserService implements OnDestroy {

    public isActiveUser: boolean = false;

    public checkUserStatus(user: UserModel) {
        return this.isActiveUser;
    }

}

I use the above service in a component, like this:

import { UserService } from '../path/to/user-service.service';
    
export class UserComponent implements OnInit {

    public isActiveUser: boolean;

    public checkUserStatus() {
        this.isActiveUser = this.UserService.checkUserStatus(user);
    }
}

The problem

In the above CompositionEvent, on the line this.isActiveUser = this.UserService.checkUserStatus(user) I get the error:

Cannot find name 'user'

What causes this error?

Answer 1

The user variable is missing in your code.

Here are scenarios to set the user variable

import { UserService } from '../path/to/user-service.service';
// Import your model with below path
import { UserModel } from '../path/to/UserModel';
    
export class UserComponent implements OnInit {

    public isActiveUser: boolean;
// Declare your user variable
user: UserModel;

    public checkUserStatus() {
        this.isActiveUser = this.UserService.checkUserStatus(user);
    }
}

Resolve your error :)