how i can to realize inheritance chain?

Have some problem with inheritance. How to implement type inheritance from Some Pencil to Another Pencil? Need: pen3.type // common

 class Pencil 
 constructor(color) 
 this.color = color;
 
 intro() 
 console.log(`this is $this.color pencil`);
 
 ;

 class SomePencil extends Pencil 
 constructor(color, type) 
 super(color);
 this.type = type;
 
 ;
 class AnotherPencil extends SomePencil 
 constructor(color,type) 
 super(color, type);
 
 ;

 let pen1 = new Pencil();
 let pen2 = new SomePencil("red", "common");
 let pen3 = new AnotherPencil("green");

 console.log("type" in pen3); // true

asked Nov 13 '18 at 16:09

disco_dinosaur

164

1

I'm not clear what you need. Do you want all instances of AnotherPencil to have type="common"?

– Nicholas Tower
Nov 13 '18 at 16:17

pen3.type !== undefined

– Keith
Nov 13 '18 at 16:23

pen3 has a property type because SomePencil has a type but that type is undefined because it hasn't been set with a value when the constructor is called. This is the way it's supposed to work. What do you want the result to be?

– Mark Meyer
Nov 13 '18 at 16:27

Remember to always favor Composition over inheritance

– David Lemon
Nov 13 '18 at 16:27

Fix it by calling const pen3 = new AnotherPencil("green", "common");

– Bergi
Nov 13 '18 at 17:26

|
show 1 more comment

Have some problem with inheritance. How to implement type inheritance from Some Pencil to Another Pencil? Need: pen3.type // common

 class Pencil 
 constructor(color) 
 this.color = color;
 
 intro() 
 console.log(`this is $this.color pencil`);
 
 ;

 class SomePencil extends Pencil 
 constructor(color, type) 
 super(color);
 this.type = type;
 
 ;
 class AnotherPencil extends SomePencil 
 constructor(color,type) 
 super(color, type);
 
 ;

 let pen1 = new Pencil();
 let pen2 = new SomePencil("red", "common");
 let pen3 = new AnotherPencil("green");

 console.log("type" in pen3); // true

asked Nov 13 '18 at 16:09

disco_dinosaur

164

1

I'm not clear what you need. Do you want all instances of AnotherPencil to have type="common"?

– Nicholas Tower
Nov 13 '18 at 16:17

pen3.type !== undefined

– Keith
Nov 13 '18 at 16:23

pen3 has a property type because SomePencil has a type but that type is undefined because it hasn't been set with a value when the constructor is called. This is the way it's supposed to work. What do you want the result to be?

– Mark Meyer
Nov 13 '18 at 16:27

Remember to always favor Composition over inheritance

– David Lemon
Nov 13 '18 at 16:27

Fix it by calling const pen3 = new AnotherPencil("green", "common");

– Bergi
Nov 13 '18 at 17:26

|
show 1 more comment

Have some problem with inheritance. How to implement type inheritance from Some Pencil to Another Pencil? Need: pen3.type // common

 class Pencil 
 constructor(color) 
 this.color = color;
 
 intro() 
 console.log(`this is $this.color pencil`);
 
 ;

 class SomePencil extends Pencil 
 constructor(color, type) 
 super(color);
 this.type = type;
 
 ;
 class AnotherPencil extends SomePencil 
 constructor(color,type) 
 super(color, type);
 
 ;

 let pen1 = new Pencil();
 let pen2 = new SomePencil("red", "common");
 let pen3 = new AnotherPencil("green");

 console.log("type" in pen3); // true

asked Nov 13 '18 at 16:09

disco_dinosaur

164

Have some problem with inheritance. How to implement type inheritance from Some Pencil to Another Pencil? Need: pen3.type // common

 class Pencil 
 constructor(color) 
 this.color = color;
 
 intro() 
 console.log(`this is $this.color pencil`);
 
 ;

 class SomePencil extends Pencil 
 constructor(color, type) 
 super(color);
 this.type = type;
 
 ;
 class AnotherPencil extends SomePencil 
 constructor(color,type) 
 super(color, type);
 
 ;

 let pen1 = new Pencil();
 let pen2 = new SomePencil("red", "common");
 let pen3 = new AnotherPencil("green");

 console.log("type" in pen3); // true

javascript oop

asked Nov 13 '18 at 16:09

disco_dinosaur

164

asked Nov 13 '18 at 16:09

disco_dinosaur

164

asked Nov 13 '18 at 16:09

disco_dinosaur

164

asked Nov 13 '18 at 16:09

disco_dinosaur

164

asked Nov 13 '18 at 16:09

disco_dinosaur

164

1

I'm not clear what you need. Do you want all instances of AnotherPencil to have type="common"?

– Nicholas Tower
Nov 13 '18 at 16:17

pen3.type !== undefined

– Keith
Nov 13 '18 at 16:23

pen3 has a property type because SomePencil has a type but that type is undefined because it hasn't been set with a value when the constructor is called. This is the way it's supposed to work. What do you want the result to be?

– Mark Meyer
Nov 13 '18 at 16:27

Remember to always favor Composition over inheritance

– David Lemon
Nov 13 '18 at 16:27

Fix it by calling const pen3 = new AnotherPencil("green", "common");

– Bergi
Nov 13 '18 at 17:26

|
show 1 more comment

1

I'm not clear what you need. Do you want all instances of AnotherPencil to have type="common"?

– Nicholas Tower
Nov 13 '18 at 16:17

pen3.type !== undefined

– Keith
Nov 13 '18 at 16:23

pen3 has a property type because SomePencil has a type but that type is undefined because it hasn't been set with a value when the constructor is called. This is the way it's supposed to work. What do you want the result to be?

– Mark Meyer
Nov 13 '18 at 16:27

Remember to always favor Composition over inheritance

– David Lemon
Nov 13 '18 at 16:27

Fix it by calling const pen3 = new AnotherPencil("green", "common");

– Bergi
Nov 13 '18 at 17:26

I'm not clear what you need. Do you want all instances of AnotherPencil to have type="common"?

– Nicholas Tower
Nov 13 '18 at 16:17

pen3.type !== undefined

– Keith
Nov 13 '18 at 16:23

pen3 has a property type because SomePencil has a type but that type is undefined because it hasn't been set with a value when the constructor is called. This is the way it's supposed to work. What do you want the result to be?

– Mark Meyer
Nov 13 '18 at 16:27

Remember to always favor Composition over inheritance

– David Lemon
Nov 13 '18 at 16:27

Fix it by calling const pen3 = new AnotherPencil("green", "common");

– Bergi
Nov 13 '18 at 17:26

|
show 1 more comment

1 Answer
1

active

oldest

votes

Inheritance will only inherit properties and not values unless they are set in the class definition itself. For example

class SomePencil extends Pencil 
 constructor(color, type) 
 super(color);
 this.type = type 
;

new way to set defaults

class SomePencil extends Pencil 
 constructor(color, type = 'common') 
 super(color);
 this.type = type;
 
;

Refer jsfiddle

answered Nov 13 '18 at 16:21

Abhidev

4,40651525

thank you! I must be more attentive

– disco_dinosaur
Nov 13 '18 at 18:54

add a comment |

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

Inheritance will only inherit properties and not values unless they are set in the class definition itself. For example

class SomePencil extends Pencil 
 constructor(color, type) 
 super(color);
 this.type = type 
;

new way to set defaults

class SomePencil extends Pencil 
 constructor(color, type = 'common') 
 super(color);
 this.type = type;
 
;

Refer jsfiddle

answered Nov 13 '18 at 16:21

Abhidev

4,40651525

thank you! I must be more attentive

– disco_dinosaur
Nov 13 '18 at 18:54

add a comment |

Inheritance will only inherit properties and not values unless they are set in the class definition itself. For example

class SomePencil extends Pencil 
 constructor(color, type) 
 super(color);
 this.type = type 
;

new way to set defaults

class SomePencil extends Pencil 
 constructor(color, type = 'common') 
 super(color);
 this.type = type;
 
;

Refer jsfiddle

answered Nov 13 '18 at 16:21

Abhidev

4,40651525

thank you! I must be more attentive

– disco_dinosaur
Nov 13 '18 at 18:54

add a comment |

Inheritance will only inherit properties and not values unless they are set in the class definition itself. For example

class SomePencil extends Pencil 
 constructor(color, type) 
 super(color);
 this.type = type 
;

new way to set defaults

class SomePencil extends Pencil 
 constructor(color, type = 'common') 
 super(color);
 this.type = type;
 
;

Refer jsfiddle

answered Nov 13 '18 at 16:21

Abhidev

4,40651525

Inheritance will only inherit properties and not values unless they are set in the class definition itself. For example

class SomePencil extends Pencil 
 constructor(color, type) 
 super(color);
 this.type = type 
;

new way to set defaults

class SomePencil extends Pencil 
 constructor(color, type = 'common') 
 super(color);
 this.type = type;
 
;

Refer jsfiddle

answered Nov 13 '18 at 16:21

Abhidev

4,40651525

answered Nov 13 '18 at 16:21

Abhidev

4,40651525

answered Nov 13 '18 at 16:21

Abhidev

4,40651525

answered Nov 13 '18 at 16:21

Abhidev

4,40651525

thank you! I must be more attentive

– disco_dinosaur
Nov 13 '18 at 18:54

add a comment |

thank you! I must be more attentive

– disco_dinosaur
Nov 13 '18 at 18:54

thank you! I must be more attentive

– disco_dinosaur
Nov 13 '18 at 18:54

add a comment |

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