javascript abstract class
//there is no way to mark a class as abstract in ES6,
//however you can force a class to behave line one by
// - forcing derived classes to override a method
// - causing the base class's contructor to throw an error so that it
// is never used to create instances of the base type*
// *Be careful, as this will cause problems if you do need derived classes
// to call super() contructor
class Foo {
constructor(text){
this._text = text;
}
/**
* Implementation optional
*/
genericMethod() {
console.log('running from super class. Text: '+this._text);
}
/**
* Implementation required
*/
doSomething() {
throw new Error('You have to implement the method doSomething!');
}
}
class Bar extends Foo {
constructor(text){
super(text);
}
genericMethod() {
console.log('running from extended class. Text: '+this._text);
}
doSomething() {
console.log('Method implemented successfully!');
}
}
let b = new Bar('Howdy!');
b.genericMethod(); //gonna print: running from extended class. Text: Howdy
b.doSomething(); //gonna print: Method implemented successfully!