Javascript - 如何在方法中获取/设置？ （例如 pineapple.is_a.fruit）

Question

I have an assignment where I'm supposed to make magic out of programming. I'm unable to find any answers online, as I do not know the search term for it (tried method in a method etc...). Appreciate any help given!

Here's what I got: I need to create a class that builds upon itself. eg

const pineapple = new Item('pineapple');
pineapple.type = fruit // this is simple

pineapple.is_a.fruit = true // this I do not know
pineapple.is.heavy = true // same thing

I do not even know where to begin. My attempt is similar to this, but I'm getting undefined.

class Thing {
  constructor(type) {
    this.type = type;
  }
  
  is_a(bool) {
    this.fruit = this.is_a(bool);
  }
}

Answer 1

Assuming that they can be defined in advance, in order to have sub-properties like pineapple.is_a.fruit , you'll need to define objects on the object's is_a and is properties. For instance (see comments):

 class Item { // `Item` rather than `Thing`, right? constructor(type) { this.type = type; // Create an `is_a` property that's an object with a `fruit` property this.is_a = { fruit: false // Or whatever the initial value should be }; // Create an `is` property that's an object with a `heavy` property this.is = { heavy: false // Or whatever the initial value should be }; } } const pineapple = new Item('pineapple'); pineapple.type = "fruit"; // I added quotes here console.log("is_a.fruit before:", pineapple.is_a.fruit); console.log("is.heavy before:", pineapple.is_a.fruit); pineapple.is_a.fruit = true; pineapple.is.heavy = true; console.log("is_a.fruit after: ", pineapple.is_a.fruit); console.log("is.heavy after: ", pineapple.is_a.fruit);