For ... In Not Yielding Methods

Given the following: export class MyClass { public dataA = 0 private dataB = 123 public myMethod(): any { return { test: 'true' } }

Solution 1:

for..in iterates over all enumerable properties of the instance and up the prototype chain. But normal methods in a class are not enumerable:

class MyClass {
    myMethod() {
        return {
            test: 'true'
        };
    }
}
console.log(Object.getOwnPropertyDescriptor(MyClass.prototype, 'myMethod').enumerable);

So it doesn't get iterated over.

If you want to iterate over non-enumerable properties as well, use Object.getOwnPropertyNames (which iterates over the object's own property names, so you'll need to do so recursively if you want all property names anywhere in the prototype chain):

const recurseLog = obj => {
  for (const name of Object.getOwnPropertyNames(obj)) {
    console.log(name);
  }
  const proto = Object.getPrototypeOf(obj);
  if (proto !== Object.prototype) recurseLog(proto);
};
class MyClass {
    dataA = 0;
    dataB = 123;
    constructor() {
        recurseLog(this);
    }
    myMethod() {
        return {
            test: 'true'
        };
    }
}
const myInst = new MyClass();

You could also make the method enumerable:

class MyClass {
    dataA = 0;
    dataB = 123;
    constructor() {
         for (const propOrMethod in this) {
            console.log({propOrMethod})
        }
    }
    myMethod() {
        return {
            test: 'true'
        };
    }
}
Object.defineProperty(MyClass.prototype, 'myMethod', { enumerable: true, value: MyClass.prototype.myMethod });
const myInst = new MyClass();

Or assign the method after the class definition:

class MyClass {
    dataA = 0;
    dataB = 123;
    constructor() {
         for (const propOrMethod in this) {
            console.log({propOrMethod})
        }
    }
}
MyClass.prototype.myMethod = () => ({ test: 'true' });
const myInst = new MyClass();

Or assign it to the instance in the constructor:

class MyClass {
    dataA = 0;
    dataB = 123;
    constructor() {
        this.myMethod = this.myMethod;
         for (const propOrMethod in this) {
            console.log({propOrMethod})
        }
    }
     myMethod() {
        return {
            test: 'true'
        };
    }
}
const myInst = new MyClass();