[英]TypeScript getting wrong this scope
I am aware of this
scopes but I am new to TypeScript and classes in JavaScript. 我知道
this
范围,但我不熟悉TypeScript和JavaScript中的类。 I am trying to access class properties within a function which is bound to a class property (to be more specific it's bound to a Socket object). 我试图访问绑定到类属性的函数中的类属性(更具体地说,它绑定到Socket对象)。
export class BrawlStarsClient {
credentials:object
dataBuffers:Array<Buffer>
pingInterval:number
constructor(credentials:object, options:object = null) {
if (!credentials) throw new Error('No credentials have been passed to constructor')
this.credentials = credentials
// Setup socket
this.client = new Socket()
this.client.on('connect', this.onConnect)
}
onConnect():void {
// In this function this refers to the socket object which is not desired
this.dataBuffers = []
this.pingInterval = null
const initPacket = packetBuilder.buildLoginPacket(this.credentials)
this.client.write(initPacket)
}
}
In onConnect()
this refers to the socket object instead of the class. 在
onConnect()
这指的是套接字对象而不是类。 What I've tried is rewriting the onConnect function to an arrow function, but that didn't help either: 我试过的是将onConnect函数重写为箭头函数,但这也无济于事:
onConnect():void {
became onConnect = ():void => {
onConnect():void {
onConnect = ():void => {
My question: 我的问题:
How can I access my class properties inside of my onConnect() function? 如何在onConnect()函数中访问我的类属性?
You can use .bind
. 你可以使用
.bind
。 .bind
will carry the arguments forward to the inner function. .bind
会将参数传递给内部函数。
this.client.on('connect', this.onConnect.bind(this));
or a arrow function. 或箭头功能。 You will manually have to pass arguments here.
您将手动必须在此处传递参数。
this.client.on('connect', () => this.onConnect());
Bind this
in constructor
: 在
constructor
绑定this
:
this.onConnect = this.onConnect.bind(this);
From the MDN documentation : 从MDN文档 :
The
bind()
method creates a new function that, when called, has itsthis
keyword set to the provided value[.]bind()
方法创建一个新函数,在调用时,将其this
关键字设置为提供的值[。]
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