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How to create an instance of concrete class from static method of abstract class

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1

1

I try to create an instance of concrete class from static method of abstract class. But I have this error:

Uncaught TypeError: Object prototype may only be an Object or null:
undefined

On this line of code in ConcreteClass.js: return extendStatics(d, b);

var __extends = (this && this.__extends) || (function () {
 var extendStatics = function (d, b) ;

My project files:

Program.ts

import AbstractClass from "./AbstractClass";

class Program

 public static Main()
 
 let instance = AbstractClass.CreateObject();
 instance.Method();
 

Program.Main();

AbstractClass.ts

import ConcreteClass from "./ConcreteClass";

export abstract class AbstractClass

 public static CreateObject()
 
 return new ConcreteClass();
 

 public abstract Method(): void;

ConcreteClass.ts

import AbstractClass from "./AbstractClass";

export class ConcreteClass extends AbstractClass

 public Method() : void
 
 console.log("Method of ConcreteClass");
 

typescript

share|improve this question

asked Mar 24 at 23:29

8Observer88Observer8

637

add a comment | 

1

1

I try to create an instance of concrete class from static method of abstract class. But I have this error:

Uncaught TypeError: Object prototype may only be an Object or null:
undefined

On this line of code in ConcreteClass.js: return extendStatics(d, b);

var __extends = (this && this.__extends) || (function () {
 var extendStatics = function (d, b) ;

My project files:

Program.ts

import AbstractClass from "./AbstractClass";

class Program

 public static Main()
 
 let instance = AbstractClass.CreateObject();
 instance.Method();
 

Program.Main();

AbstractClass.ts

import ConcreteClass from "./ConcreteClass";

export abstract class AbstractClass

 public static CreateObject()
 
 return new ConcreteClass();
 

 public abstract Method(): void;

ConcreteClass.ts

import AbstractClass from "./AbstractClass";

export class ConcreteClass extends AbstractClass

 public Method() : void
 
 console.log("Method of ConcreteClass");
 

typescript

share|improve this question

asked Mar 24 at 23:29

8Observer88Observer8

637

add a comment | 

I try to create an instance of concrete class from static method of abstract class. But I have this error:

Uncaught TypeError: Object prototype may only be an Object or null:
undefined

On this line of code in ConcreteClass.js: return extendStatics(d, b);

var __extends = (this && this.__extends) || (function () {
 var extendStatics = function (d, b) ;

My project files:

Program.ts

import AbstractClass from "./AbstractClass";

class Program

 public static Main()
 
 let instance = AbstractClass.CreateObject();
 instance.Method();
 

Program.Main();

AbstractClass.ts

import ConcreteClass from "./ConcreteClass";

export abstract class AbstractClass

 public static CreateObject()
 
 return new ConcreteClass();
 

 public abstract Method(): void;

ConcreteClass.ts

import AbstractClass from "./AbstractClass";

export class ConcreteClass extends AbstractClass

 public Method() : void
 
 console.log("Method of ConcreteClass");
 

typescript

share|improve this question

asked Mar 24 at 23:29

8Observer88Observer8

637

var __extends = (this && this.__extends) || (function () {
 var extendStatics = function (d, b) ;

import AbstractClass from "./AbstractClass";

class Program

 public static Main()
 
 let instance = AbstractClass.CreateObject();
 instance.Method();
 

Program.Main();

import ConcreteClass from "./ConcreteClass";

export abstract class AbstractClass

 public static CreateObject()
 
 return new ConcreteClass();
 

 public abstract Method(): void;

import AbstractClass from "./AbstractClass";

export class ConcreteClass extends AbstractClass

 public Method() : void
 
 console.log("Method of ConcreteClass");
 

share|improve this question

asked Mar 24 at 23:29

8Observer88Observer8

637

share|improve this question

asked Mar 24 at 23:29

8Observer88Observer8

637

asked Mar 24 at 23:29

8Observer88Observer8

637

asked Mar 24 at 23:29

8Observer88Observer8

637

1 Answer
1

active

oldest

votes

2

The problem has to do with a circular import. AbstractClass and ConcreteClass are importing each other and the definition of each is making use of the other. The specific problem is that when ConcreteClass is extending AbstractClass, the AbstractClass is still undefined, because it is waiting for ConcreteClass to finish loading. As a result, the runtime is seeing something like vaguely this:

import AbstractClass from "./AbstractClass";

// at runtime AbstractClass has not finished loading yet so it is undefined
export class ConcreteClass extends undefined

 public Method() : void
 
 console.log("Method of ConcreteClass");
 

share|improve this answer

edited Mar 25 at 1:18

answered Mar 25 at 1:02

Shaun LuttinShaun Luttin

66.2k39247306

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I did not hear about the circular import problem before. Now I understand what I need to search in the Internet. Thank you very much.
  
  – 8Observer8
  Mar 25 at 11:34
  

  
  
  
  

add a comment | 

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2

The problem has to do with a circular import. AbstractClass and ConcreteClass are importing each other and the definition of each is making use of the other. The specific problem is that when ConcreteClass is extending AbstractClass, the AbstractClass is still undefined, because it is waiting for ConcreteClass to finish loading. As a result, the runtime is seeing something like vaguely this:

import AbstractClass from "./AbstractClass";

// at runtime AbstractClass has not finished loading yet so it is undefined
export class ConcreteClass extends undefined

 public Method() : void
 
 console.log("Method of ConcreteClass");
 

share|improve this answer

edited Mar 25 at 1:18

answered Mar 25 at 1:02

Shaun LuttinShaun Luttin

66.2k39247306

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I did not hear about the circular import problem before. Now I understand what I need to search in the Internet. Thank you very much.
  
  – 8Observer8
  Mar 25 at 11:34
  

  
  
  
  

add a comment | 

2

The problem has to do with a circular import. AbstractClass and ConcreteClass are importing each other and the definition of each is making use of the other. The specific problem is that when ConcreteClass is extending AbstractClass, the AbstractClass is still undefined, because it is waiting for ConcreteClass to finish loading. As a result, the runtime is seeing something like vaguely this:

import AbstractClass from "./AbstractClass";

// at runtime AbstractClass has not finished loading yet so it is undefined
export class ConcreteClass extends undefined

 public Method() : void
 
 console.log("Method of ConcreteClass");
 

share|improve this answer

edited Mar 25 at 1:18

answered Mar 25 at 1:02

Shaun LuttinShaun Luttin

66.2k39247306

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I did not hear about the circular import problem before. Now I understand what I need to search in the Internet. Thank you very much.
  
  – 8Observer8
  Mar 25 at 11:34
  

  
  
  
  

add a comment | 

The problem has to do with a circular import. AbstractClass and ConcreteClass are importing each other and the definition of each is making use of the other. The specific problem is that when ConcreteClass is extending AbstractClass, the AbstractClass is still undefined, because it is waiting for ConcreteClass to finish loading. As a result, the runtime is seeing something like vaguely this:

import AbstractClass from "./AbstractClass";

// at runtime AbstractClass has not finished loading yet so it is undefined
export class ConcreteClass extends undefined

 public Method() : void
 
 console.log("Method of ConcreteClass");
 

share|improve this answer

edited Mar 25 at 1:18

answered Mar 25 at 1:02

Shaun LuttinShaun Luttin

66.2k39247306

import AbstractClass from "./AbstractClass";

// at runtime AbstractClass has not finished loading yet so it is undefined
export class ConcreteClass extends undefined

 public Method() : void
 
 console.log("Method of ConcreteClass");
 

share|improve this answer

edited Mar 25 at 1:18

answered Mar 25 at 1:02

Shaun LuttinShaun Luttin

66.2k39247306

answered Mar 25 at 1:02

Shaun LuttinShaun Luttin

66.2k39247306

answered Mar 25 at 1:02

Shaun LuttinShaun Luttin

66.2k39247306