访问angular2中的全局变量

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

@Injectable({
  providedIn: 'root'
})
export class GlobalService {
  private globalVariable: string;

  constructor() { }

  setGlobalVariable(value: string): void {
    this.globalVariable = value;
  }

  getGlobalVariable(): string {
    return this.globalVariable;
  }
}

import { Component } from '@angular/core';
import { GlobalService } from './global.service';

@Component({
  selector: 'app-root',
  template: `
    <h1>Global Variable: {{ globalVariable }}</h1>
    <button (click)="updateGlobalVariable()">Update Global Variable</button>
  `
})
export class AppComponent {
  globalVariable: string;

  constructor(private globalService: GlobalService) {
    this.globalVariable = globalService.getGlobalVariable();
  }

  updateGlobalVariable(): void {
    this.globalService.setGlobalVariable('New Value');
    this.globalVariable = this.globalService.getGlobalVariable();
  }
}