我正在學習 WebGL，并開始使用 p5.js 和 angular 開發 Sketch 應用程序。我在組件文件中定義了布爾變量，因此我想在繪圖函數中觸發特定函數，如橢圓、矩形、直線等。這些布爾變量由另一個組件中的按鈕管理。我收到core.js:6014 錯誤類型錯誤：無法讀取未定義的屬性“isRectangleMode”組件文件：import { Component, OnInit } from '@angular/core';import * as p5 from 'p5';import { Subscription } from 'rxjs';import { HomeService } from '../home.service';@Component({  selector: 'app-doodle-area',  templateUrl: './doodle-area.component.html',  styleUrls: ['./doodle-area.component.css']})export class DoodleAreaComponent implements OnInit {  private p5Init : any;  modeSubs : Subscription;  modeSelected : string = null;  isCircleMode : boolean = false;  isEllipseMode : boolean = false;  isRectangleMode : boolean = false;  isLineMode : boolean = false;  isPointMode : boolean = false;  isBrushMode : boolean = false;  isPenMode : boolean = false;  constructor(private homeService : HomeService) { }  ngOnInit() {    this.createCanvas();    this.homeService.modeSelected      .subscribe(modeSelected => {        this.modeSelected = modeSelected;        console.log(this.modeSelected);        if(this.modeSelected) {          this.modeReset();          if(this.modeSelected === "circle") {            this.isCircleMode = true;          } else if(this.modeSelected === 'ellipse') {            this.isEllipseMode = true;          } else if(this.modeSelected === 'rectangle') {            this.isRectangleMode = true;          } else if(this.modeSelected === 'line') {            this.isLineMode = true;          } else if(this.modeSelected === 'point') {            this.isPointMode = true;          } else if(this.modeSelected === 'brush') {            this.isBrushMode = true;          } else if(this.modeSelected === 'pen') {            this.isPenMode = true;          }        }      });  }}控制臺截圖：