How to implement copy inheritance in js

This article is about how js implements copy inheritance. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

The parent class code is as follows:

/ / define an animal class function Animal (name) {/ / attribute this.name = name | | 'Animal'; / / instance method this.sleep = function () {console.log (this.name +' sleeping!') ;}} / / prototype method Animal.prototype.eat = function (food) {console.log (this.name + 'eating:' + food);}; copy inheritance function Cat (name) {var animal = new Animal (); for (var p in animal) {Cat.prototype [p] = animal [p] } / / the following implementation modifies the prototype object, which will cause a single instance to modify name, which will affect the name value of all instances / / Cat.prototype.name = name | | 'Tom'; incorrect statement, the next sentence is the correct implementation this.name = name | |' Tom';} / / Test Codevar cat = new Cat (); console.log (cat.name); console.log (cat.sleep ()); console.log (cat instanceof Animal) / / falseconsole.log (cat instanceof Cat); / / true

Features:

Support for multiple inheritance

Disadvantages:

Low efficiency and high memory footprint (because you want to copy the properties of the parent class)

Cannot get methods that cannot be enumerated in the parent class (methods that cannot be enumerated, cannot be accessed using for in)

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