JavaScript入門者　プロパティを用意しているのにエラーになる原因が知りたい。[ Uncaught RangeError: Maximum call stack size exceeded ]

提示コードですがコメント部///のコードですがなぜエラーになるのでしょか？以下のError提示コード部です。参考サイトと同じようにコードを作ったのですがエラーになります。これは何が原因なのでしょうか？

参考サイト：　https://www.tohoho-web.com/js/class.htm

Error
1Game.js:49 Uncaught RangeError: Maximum call stack size exceeded
2    at Player.get position [as position] (Game.js:49)
3    at Player.get position [as position] (Game.js:49)
4    at Player.get position [as position] (Game.js:49)
5    at Player.get position [as position] (Game.js:49)
6    at Player.get position [as position] (Game.js:49)
7    at Player.get position [as position] (Game.js:49)
8    at Player.get position [as position] (Game.js:49)
9    at Player.get position [as position] (Game.js:49)
10    at Player.get position [as position] (Game.js:49)
11    at Player.get position [as position] (Game.js:49)
12get position @ Game.js:49
13get position @ Game.js:49
14get position @ Game.js:49
15省略
16get position @ Game.js:49
17get position @ Game.js:49
18get position @ Game.js:49
19get position @ Game.js:49
20
21Show 170 more frames
22Main.js:19 Uncaught ReferenceError: Cannot access 'entry' before initialization
23    at draw (Main.js:19)
24    at p5._main.default.redraw (p5.js:70809)
25    at _draw (p5.js:63046)

js
1
2class Enemy
3{
4      constructor(pos)
5      {
6            this.position = new Vector(pos.x,pos.y);
7            this.alive = true;
8            this.size = 50;
9      }
10
11      Init(pos)
12      {
13            this.position = new Vector(pos.x,pos.y);
14            this.alive = true;
15
16      }
17
18      Update()
19      {
20
21      }
22
23      Renderer()
24      {
25            //fill(color(0,100,0));
26            line(this.position.x,this.position.y,this.position.x + this.size,this.position.y + this.size);
27//            triangle(this.position.x,this.position.y + this.size,
28  //                this.position.x - this.size,this.position.y - this.size,
29    //              this.position.x + this.size,this.position.y - this.size);
30
31      }
32
33}
34
35
36class Player
37{
38      constructor()
39      {
40            this.acce = new Vector(0,0);  //sin波
41            this.position = new Vector(300,300);
42            this.acce = new Vector(0,0);
43            this.alive = true;
44            this.size = 100;
45      }
46////////////////////////////////////////////////////////////////
47      get position()
48      {
49            return this.position;
50      }
51////////////////////////////////////////////////////////////////
52      set position(p)
53      {
54            this.position.x = p.x;
55            this.position.y = p.y;
56
57      }
58
59
60      Update()
61      {
62            KeyInput(this.position,this.acce);
63      }
64
65
66      Renderer()
67      {
68            line(this.position.x,this.position.y,this.position.x + this.size,this.position.y + this.size);
69
70      }
71
72}
73
74class Bullet
75{
76
77}
78
79
80class Game 
81{
82
83      //オブジェクトプール
84      EnemyInstance(pos)
85      {
86            this.enemy.forEach(item =>
87            { 
88
89                  if(item.alive === false)
90                  {
91                        item.Init(pos);
92                        return;     
93                  }
94
95
96            });
97
98            this.enemy.push(new Enemy(new Vector(pos.x,pos.y)));
99            return;
100      }
101
102      constructor()
103      {
104
105            this.enemy = new Array();     //Enemy 配列
106            this.Player = new Player();   //Player
107
108            for(let i = 0; i< 10; i++)
109            {
110                  this.EnemyInstance(new Vector(100 + 40 * i,100));
111            }
112
113
114      }
115
116
117      Collision(posA,posB)
118      {
119            if(Collision.LineSegment(posA,posB) == true)
120            {
121                  return true;
122            }
123            else
124            {
125                  return false;
126            }
127      }
128
129      Update()
130      {
131            this.enemy.forEach(item =>
132            {
133                  item.Update();
134                  if((this.Collision(this.player.position,item.position) === true) && (item.alive === true))
135                  {
136                        item.alive = false;
137                  }
138
139            });
140
141
142
143
144      }
145
146
147      Renderer()
148      {
149            this.enemy.forEach( item => item.Renderer());     
150            this.plyer.Renderer();      
151      }
152
153
154
155
156
157
158}

行動規範の内容に同意します

回答1件

ベストアンサー

これは何が原因なのでしょうか？

position() を再帰的に呼び出しているのが原因です。
メンバ変数名と getter の名前が同じである為に、position() を繰り返し呼び出してしまっています。
どちらかを別名に変えてみて下さい。以下はメンバ変数名を変更した場合の例です。

javascript
1class Player {
2    constructor() {
3        this.acce = new Vector(0, 0); //sin波
4        this._position = new Vector(300, 300);  // "this.position" → "this._position"
5        this.acce = new Vector(0, 0);
6        this.alive = true;
7        this.size = 100;
8    }
9    ////////////////////////////////////////////////////////////////
10    get position() {
11        return this._position;  // "this.position" → "this._position"
12    }
13    ////////////////////////////////////////////////////////////////
14    set position(p) {
15        this._position.x = p.x;  // "this.position" → "this._position"
16        this._position.y = p.y;  // "this.position" → "this._position"
17    }
18      :
19}

投稿2021/09/18 12:53

cx20

総合スコア4648

退会済みユーザー

2021/09/18 13:25

なるほど以下ようにしたのですがエラー出ますなぜでしょうか？「　Uncaught TypeError: Cannot read properties of undefined (reading 'getPosition') at Game.js:134 at Array.forEach (<anonymous>) at Game.Update (Game.js:131) at Entry.Loop (Entry.js:13) at draw (Main.js:19) at p5._main.default.redraw (p5.js:70809) at _draw (p5.js:63046)　」「 constructor() { this.acce = new Vector(0,0); //sin波 this.position = new Vector(300,300); this.acce = new Vector(0,0); this.alive = true; this.size = 100; } get getPosition() { return this.position; } set setPosition(p) { this.position.x = p.x; this.position.y = p.y; } ////////////////////////////////↓です。 if((this.Collision(this.player.getPosition,item.position) === true) && (item.alive === true)) 」