如何将数据从组件传递到包含数组的 .ts 文件？

Question

I'm working on a budgeting app. I have a component that holds values I would like to pass to an array that is stored in it's own file. I am able to get data from the array but I can't seem to figure out how to push data into the array.

Is there a way to even do this or would I have to create another component and store the array in that component?

input.component.ts

import { Component, OnInit, Input } from '@angular/core';
import { USERS } from '../mock-users';
import { Users } from '../Users';
//import { Users } from '../Users';

@Component({
  selector: 'app-input',
  templateUrl: './input.component.html',
  styleUrls: ['./input.component.css']
})
export class InputComponent implements OnInit {

  @Input() description: string;
  @Input() date: Date;
  @Input() amount: number;
  @Input() category: string;


  constructor() { }

  ngOnInit() {
  }

  addExpense() {

    console.log('expense added');

  }

}

mock-users.ts

import { Users } from './Users';

export const USERS: Users[] = [
    {
        id: 1,
        name: 'Keenan',
        username: 'keenan.kaufman',
        password: 'admin',
        expenses: [{
                    //var myDate = new Date('2019-5-2T00:00:00');
                    date: new Date('2019-5-2T00:00:00'),
                    description: 'Electric Bill',
                    amount: 42,
                    category: 'Utilites'
                    },
                    {
                    date: new Date('2019-5-2T00:00:00'),
                    description: 'Rent',
                    amount: 350,
                    category: 'Rent' 
                    }]
    }

];

Answer 1

Define a really basic service that hold the data for you, this way you can inject it into any component you need and freely access the data.

---

import { Injectable } from '@angular/core';

@Injectable(
  {
    providedIn: 'root'
  }
)
export class DataService{

  constructor() { }

  public users : Users[] = [
  {
    id: 1,
    name: 'Keenan',
    username: 'keenan.kaufman',
    password: 'admin',
    expenses: [{
                //var myDate = new Date('2019-5-2T00:00:00');
                date: new Date('2019-5-2T00:00:00'),
                description: 'Electric Bill',
                amount: 42,
                category: 'Utilites'
                },
                {
                date: new Date('2019-5-2T00:00:00'),
                description: 'Rent',
                amount: 350,
                category: 'Rent' 
                }]
     }];
   }
}

---

In one of your components you can then access the data like so.

public usersLocal: Users[];
constructor(private dataService: DataService) {}

public ngOnInit(): void
{
    this.usersLocal = this.dataService.users;
    console.log(this.usersLocal); 
    // array held in service by reference can now push and / splice etc 
}

You could define functions in the service for adding to and removing from the array, and any other actions you require surrounding the data.

---

Angulars Documentation .