如何用一个class扩展多个classes（不是多重继承）？

Question

这里有几个 JS classes。 GrandChildOne 和 GrandChildTwo class 是相同的，但扩展了不同的父 class。由于他们的代码相同，我正在寻找摆脱这种重复的方法。换句话说，我想要一个 class（我们称它为 GrandChild）并用它来扩展 ChildOne 和 ChildTwo classes。有什么建议吗？

class Parent {
  someParentMethod () {
     console.log('Parent')
  }
}

class ChildOne extends Parent {
   someChildOneMethod () {
     console.log('someChildOneMethod')
  }
}

class ChildTwo extends Parent {
   someChildTwoMethod () {
     console.log('someChildTwoMethod')
   }
}


// THE CLASSES BELOW ARE IDENTICAL
class GrandChildOne extends ChildOne {
   someGrandChildMethod() {
     console.log('someGrandChildMethod')
   }
}
class GrandChildTwo extends ChildTwo {
   someGrandChildMethod() {
     console.log('someGrandChildMethod')
   }
}

const grandChildOne = new GrandChildOne()
const grandChildTwo = new GrandChildTwo()

Answer 1

您可以为此使用 Mix-ins (example in MDN)

会是这样的：

class Parent {
  someParentMethod () {
     console.log('Parent')
  }
}

class ChildOne extends Parent {
   someChildOneMethod () {
     console.log('someChildOneMethod')
  }
}

class ChildTwo extends Parent {
   someChildTwoMethod () {
     console.log('someChildTwoMethod')
   }
}


// define GrandChild as a Mix-in:
let GrandChild = Base => class extends Base {
  someGrandChildMethod() {
     console.log('someGrandChildMethod')
   }
};

//Then:
class GrandChildOne extends GrandChild(ChildOne) { }
class GrandChildTwo extends GrandChild(ChildTwo) { }

const grandChildOne = new GrandChildOne()
const grandChildTwo = new GrandChildTwo()

grandChildOne.someChildOneMethod();
grandChildTwo.someChildTwoMethod();

如何用一个class扩展多个classes（不是多重继承）？

How to use one class to extend multiple classes (not multiple inheritance)?

javascript

javascript-objects

javascript-inheritance