typescript MyObject.instanceOf()

Question

All of our typescript classes inherit (directly or indirectly) from:

export class WrObject {     className:string;      public instanceOf(name : String) : boolean {         return this.className === name;     } } 

We then declare a subclass as:

export class Section extends WrObject {     public static CLASS_NAME = 'Section';     className = Section.CLASS_NAME;          public instanceOf(name : String) : boolean {             if (this.className === name)                 return true;             return super.instanceOf(name);         }  } 

And you can then check with:

if (obj.instanceOf(Section.CLASS_NAME)) 

It all works great. However, I think it would be cleaner if we could do:

if (obj.instanceOf(Section)) 

Is there any way to do that? Or any suggestions as to a better approach?

thanks - dave

Answer 1

If you are willing to accept the prototypal nature of JavaScript you can just use instanceof which checks the prototype chain:

class Foo{} class Bar extends Foo{} class Bas{}  var bar = new Bar();  console.log(bar instanceof Bar); // true console.log(bar instanceof Foo); // true console.log(bar instanceof Object); // true  console.log(bar instanceof Bas); // false 

Answer 2

You can do it. Just replace your instanceOf implementation with this one:

public instanceOf(cls: { CLASS_NAME: string; }) {     return cls.CLASS_NAME === this.className || super.instanceOf(cls); }