CODEWITHSUNDEEP
javascriptclassinheritancepropertiesstatic
sed lex
sed lex

Reputation: 80

Inheriting static properties in Javascript

The design pattern I use in my current project is:

var MyConstructor = function() { ... };
MyConstructor.STATIC_PROPERTY = 'static';

Now if i want to inherit from MyConstructor class, I'd do:

var ChildClass = function() { ... };
ChildClass.prototype = new MyConstructor(); // Or Object.create(...)
ChildClass.prototype.constructor = ChildClass;

Problem is ChildClass.STATIC_PROPERTY is undefined / not inherited ...

Is there a way to fix that?

Secondary question:

If I console.log(MyConstructor), I'd get function() { ...} and nothing about MyConstructor.STATIC_PROPERTY when it's actually there. Where is that STATIC_PROPERTY stored in the end? How can I check/display it?

Upvotes: 3

Views: 2230

Answers (1)

Bergi
Bergi

Reputation: 665536

Use an ES6 class, which does prototypically inherit from the parent class (constructor function object):

function MyConstructor() { /* … */ }
MyConstructor.STATIC_PROPERTY = 'static';

class ChildClass extends MyConstructor { /* … */ }
console.log(ChildClass.STATIC_PROPERTY);

The alternative would be to either copy all properties (like with Object.assign) or to use Object.setPrototypeOf on the ChildClass.

Upvotes: 3

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