I was looking through MDN's doc on Object.create() to see how it works while looking through someones code. But here's what I'm wondering now, as a typescript newbie.
How can I get their example to work with typescript while not using a class?
In a ts file, I can't find a way around this error without using js classes: 'this' implicitly has type 'any' because it does not have a type annotation.
EDIT:
I come close if I do something like this:
function Shape(this: any) {
this.x = 0;
this.y = 0;
}
// superclass method
Shape.prototype.move = function(x: any, y: any) {
this.x += x;
this.y += y;
console.info('Shape moved.');
};
// Rectangle - subclass
function Rectangle(this: any) {
Shape.call(this); // call super constructor.
}
// subclass extends superclass
Rectangle.prototype = Object.create(Shape.prototype);
//If you don't set Rectangle.prototype.constructor to Rectangle,
//it will take the prototype.constructor of Shape (parent).
//To avoid that, we set the prototype.constructor to Rectangle (child).
Rectangle.prototype.constructor = Rectangle;
const rect = new Rectangle();
console.log('Is rect an instance of Rectangle?', rect instanceof Rectangle); // true
console.log('Is rect an instance of Shape?', rect instanceof Shape); // true
rect.move(1, 1); // Outputs, 'Shape moved.'
Oh...this seems to do it...
function Shape(this: any) {
this.x = 0;
this.y = 0;
}
// superclass method
Shape.prototype.move = function(x: any, y: any) {
this.x += x;
this.y += y;
console.log('Shape moved.');
};
// Rectangle - subclass
function Rectangle(this: any) {
Shape.call(this); // call super constructor.
}
// subclass extends superclass
Rectangle.prototype = Object.create(Shape.prototype);
//If you don't set Rectangle.prototype.constructor to Rectangle,
//it will take the prototype.constructor of Shape (parent).
//To avoid that, we set the prototype.constructor to Rectangle (child).
Rectangle.prototype.constructor = Rectangle;
const rect = new (Rectangle as any)();
console.log('Is rect an instance of Rectangle?', rect instanceof Rectangle); // true
console.log('Is rect an instance of Shape?', rect instanceof Shape); // true
rect.move(1, 1); // Outputs, 'Shape moved.'