In the following code, the bind method has been called so that this.flavour does not become undefined when bake is called from another class.
interface CakeEvent{
onBake(flour:number):void
}
class Cake {
private listener: CakeEvent
addChocolate(listener: CakeEvent) {
this.listener = listener
}
onBake(flour: number) {
this.listener.onBake(flour)
}
}
class Chocolate {
private flavour = 'vanilla'
private bake(flour:number) {
console.log(this.flavour, flour)
}
constructor(private cake: Cake) {
const listener: CakeEvent = {
onBake: this.bake.bind(this) // <- Here
}
this.cake.addChocolate(listener)
}
}
const cake = new Cake()
const choco = new Chocolate(cake)
cake.onBake(4564)
However, as soon as the method bind is called on the function bake, this type becomes any. This means that Typescript will not throw a compilation error if its property does not match the interface definition CakeEvent. If it becomes any, the interface CakeEvent is a useless waste of time.
退还任何物品的动机是什么？它不应该返回相同类型的函数吗？
当前，有什么解决方法可以防止这种情况发生？
from node_modules/typescript/lib.es5.d.ts
/**
* For a given function, creates a bound function that has the same body as the original function.
* The this object of the bound function is associated with the specified object, and has the specified initial parameters.
* @param thisArg An object to which the this keyword can refer inside the new function.
* @param argArray A list of arguments to be passed to the new function.
*/
bind(this: Function, thisArg: any, ...argArray: any[]): any;
