angular2 - passing data object between components

Question

Looking for some help, if possible.

I have a data object located in one component, received from a REST call. It contains user details that I would like to share across components, but I am having trouble.

What is the best way to pass this object over to another component, so I can use the details?

Ex. The data object is named user, and I want to share the user._id created from the database and received from the REST call with a separate component.

Thanks everyone for any help.

COMPONENT ONE (contains user data object):

import {Component} from 'angular2/core';
import {ROUTER_DIRECTIVES, Router, Location} from 'angular2/router';
import {Control, FORM_DIRECTIVES, NgIf} from 'angular2/common';
import {UserLogin} from './navbar.login.service';
import {LoginService} from './navbar.login.service';
import {AccountDataService} from '../account/account.data.service';
import {User} from '../account/account.model';

@Component({
selector: 'navbar',
templateUrl: './app/navbar/navbar.component.html',
directives: [ROUTER_DIRECTIVES],
providers: [LoginService, AccountDataService]
})

export class NavbarComponent {

model: UserLogin;
user: User;
message: string;

constructor(private _service: LoginService, public _userService: AccountDataService,
    private router: Router, private location: Location) {
    this.model = this._service.modelInstance();
    this.user = this._userService.modelInstance();
}

onSubmit() {

    this._service.rawPost('?username=' + this.model.userName
        + '&password=' + this.model.password)
        .subscribe(res => {
            if (res.status === 200) {
                this.message = 'You have been logged in with: ' + this.model.userName;
                this.router.navigate(['Dashboard']);
                this._userService.read('/username/' + this.model.userName)
                    .subscribe(user => {
                        this.user = user; // <--- NEED THIS OBJECT PASSED AND SHARED!!
                })
                    });
            } else {
                this.message = 'Username or Password is not correct';
            }
        },
        error => {
            console.log("Response = %s", JSON.stringify(error));
            if (error.status == 401) {
                this.message = 'Username or Password is not correct';
            }
        });

}

toggleMenu() {
    this.menuActive = !this.menuActive;
}

logout() { //NOT SURE ABOUT THIS!!!
    // clears browser history so a user can't navigate with back button
    // this.location.replaceState('/');
    this.router.navigate(['Home']);
}

COMPONENT TWO Needs adjusting. Can't get the user object above to pass in. Not even sure where to start at this point.

import {Component, OnInit} from 'angular2/core';
import {UserCase} from './case/case.model';
import {User} from '../account/account.model';
import {ROUTER_DIRECTIVES} from 'angular2/router'; 
import {AccountDataService} from '../account/account.data.service';
import {NavbarComponent} from '../navbar/navbar.component';

@Component({
selector: 'dashboard',
templateUrl: './app/dashboard/dashboard.component.html',
directives: [NavbarComponent],
providers: [ROUTER_DIRECTIVES, AccountDataService],
})

export class DashboardComponent implements OnInit {

public user: User;
public userCase;
public userCases: UserCase[] = []

ngOnInit() {
    // Also trying to get each userCase object into the userCases array (not currently working)

    this._caseService.read('/user/' + this.user._id) //this.user not currently defined.
        .subscribe(userCase => {
            this.userCase = userCase;
        });

    this.userCases.push(this.userCase);
}

constructor(private _caseService: CaseDataService, private _userService: AccountDataService) {
    this.user = this._userService.modelInstance();
    this.userCase = this._caseService.modelInstance();
    this.userCases = [];
}

}

Answer 1

The best way is to just pass the data as an input for "Component Two".

So, inside component one, you should do:

<dashboard [user]="user"></dashboard>

and inside Component Two you should add:

@Input() user;

You will not be able to access this input inside Component Two's contractor, only inside its "ngOnInit". See this for reference