[英]Typescript global variables becoming undefined after function call
In my code, I have two global variables defined as 在我的代码中,我有两个全局变量定义为
constructor() {
this.map = new Map();
this.player = new Player([], "");
}
I can access these variables through my program normally, however when I call one of my functions this.handleInput(Command.GO, "north");
我可以通过程序正常访问这些变量,但是当我调用函数之一
this.handleInput(Command.GO, "north");
where Command.GO translates to "GO" and "north" is a direction to go to, all of my global variables become undefined. 在Command.GO转换为“ GO”而“ north”是一个方向的地方,我所有的全局变量都变得不确定。 In the handleInput method,
在handleInput方法中,
private handleInput(cmd:Command, arg:string):boolean {
console.log("Handling", cmd, "with argument '"+arg+"'");
if (cmd === "GO") {
console.log(`You go ${arg}`);
this.player.setCurrentLocation(this.map.getNextLocation(arg).getName());
this.updateGame(this.map.getNextLocation(arg));
}
}
I immediately get errors that this.player and this.map are undefined, however they were not undefined before I called the method! 我立即收到错误,指出this.player和this.map是未定义的,但是在调用该方法之前,它们并不是未定义的! Is there something about global variables in TS/JS that I'm not grasping?
我不了解TS / JS中关于全局变量的某些信息吗?
Your this
is most likely referring to another object depending on how handleInput
is being called. 你
this
是最有可能涉及到另一个对象取决于如何handleInput
被调用。 In your contructor()
, either bind
handleInput
to this
or change your handleInput
to use arrow function: 在你的
contructor()
或者bind
handleInput
到this
或更改handleInput
使用箭头功能:
constructor() {
this.handleInput = this.handleInput.bind(this);
}
Or: 要么:
handleInput = (cmd:Command, arg:string):boolean => {}
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