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java-script:multiple-inheritance [2023/07/26 19:01] odeftajava-script:multiple-inheritance [2023/07/26 19:39] (current) odefta
Line 12: Line 12:
 ===== Java Script Mixins ===== ===== Java Script Mixins =====
  
-A **mixin** is a class whose methods are intended to be added to (or "mixed in" to) other classes. +==== Mixins using class syntax ==== 
 + 
 +::A **mixin** is a class whose methods are intended to be added to (or "mixed in" to) other classes.:: \\   
 +AnimalMixin is a function that takes a base class and returns a new class that extends the base class and adds the eats method. \\ ;;;Then Employee extends AnimalMixin(Person) - effectively combining Person and Animal.;;; \\ Also, note that super refers to the parent class, so calling super.description() in Employee will call description on Person, not Animal.
  
 Example: Example:
Line 25: Line 28:
     description() {     description() {
         return `A person named ${this.name} who is ${this.age} years old`;         return `A person named ${this.name} who is ${this.age} years old`;
-    } 
-} 
- 
-class Animal { 
-    eats() { 
-        return `${this.name} eats.`; 
     }     }
 } }
Line 36: Line 33:
 const AnimalMixin = Base => class extends Base { const AnimalMixin = Base => class extends Base {
     eats() {     eats() {
-        return `${this.name} eats.`;+        return `${this.name} eats like an animal.`;
     }     }
 }; };
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 console.log(employee.description()); // An employee is also A person named Aurel who is 30 years old console.log(employee.description()); // An employee is also A person named Aurel who is 30 years old
 </code> </code>
 +
 +<note warning>
 +While mixins can be useful for sharing behavior between classes, they should be used sparingly as they can make code more complex and harder to follow.
 +</note>
 +
 +==== Mixins using Object.assign ====
 +
 +Same functionality can be achieved using **Object.assign** approach. \\
 +;;;In this case, we're directly adding the methods from AnimalMixin to the prototype of Employee class using Object.assign(). This way, all instances of Employee will have access to the eats method.;;;
 +
 +<code javascript Person.js>
 +let AnimalMixin = {
 +    eats() {
 +        return `${this.name} eats.`;
 +    }
 +};
 +
 +class Employee {
 +    constructor(name, age, salary, jobTitle) {
 +        this.name = name;
 +        this.age = age;
 +        this.salary = salary;
 +        this.jobTitle = jobTitle;
 +    }
 +
 +    description() {
 +        return `A person named ${this.name} who is ${this.age} years old`;
 +    }
 +}
 +
 +Object.assign(Employee.prototype, AnimalMixin);
 +
 +let employee = new Employee("Aurel", 30, 15000, "CEO boss");
 +console.log(employee.eats()); // Aurel eats.
 +</code>
 +
 +<note>
 +Using class syntax can be more straightforward if you're already working with classes and want to take advantage of built-in class features like super calls and static properties/methods.
 +</note>
 +
 +<note>
 +On the other hand, Object.assign() can be more flexible and dynamic, since it allows you to copy methods onto any object, not just class prototypes.
 +</note>
 +
 +
 +
  
  
java-script/multiple-inheritance.1690387300.txt.gz · Last modified: 2023/07/26 19:01 by odefta