Get properties of class in typescript

Question

I\'ve the following class:

export class Test {

        private _rowsCount: string;
        public get RowsCount(): string {
            return this._rowsCou         


        

Answer 1

If you need to only get the getters/setters, then you'll need to do something like:

class Test {
    ...

    public static getGetters(): string[] {
        return Object.keys(this.prototype).filter(name => {
            return typeof Object.getOwnPropertyDescriptor(this.prototype, name)["get"] === "function"
        });
    }

    public static getSetters(): string[] {
        return Object.keys(this.prototype).filter(name => {
            return typeof Object.getOwnPropertyDescriptor(this.prototype, name)["set"] === "function"
        });
    }
}

Test.getGetters(); // ["RowsCount", "RowsCount2"]
Test.getSetters(); // ["RowsCount", "RowsCount2"]

(code in playground)

---

You can put the static methods in a base class, and then when you extend it the subclass will have those static methods as well:

class Base {
    public static getGetters(): string[] {
        return Object.keys(this.prototype).filter(name => {
            return typeof Object.getOwnPropertyDescriptor(this.prototype, name)["get"] === "function"
        });
    }

    public static getSetters(): string[] {
        return Object.keys(this.prototype).filter(name => {
            return typeof Object.getOwnPropertyDescriptor(this.prototype, name)["set"] === "function"
        });
    }
}

class Test extends Base {
   ...
}

Test.getGetters(); // work the same

(code in playground)

If you want these methods to be instance methods then you can do this:

class Base {
    public getGetters(): string[] {
        return Object.keys(this.constructor.prototype).filter(name => {
            return typeof Object.getOwnPropertyDescriptor(this.constructor.prototype, name)["get"] === "function"
        });
    }

    public getSetters(): string[] {
        return Object.keys(this.constructor.prototype).filter(name => {
            return typeof Object.getOwnPropertyDescriptor(this.constructor.prototype, name)["set"] === "function"
        });
    }
}

The change is that instead of using this.prototype you're using this.constructor.prototype.
Then you simply:

let a = new Test();
a.getGetters(); // ["RowsCount", "RowsCount2"]

(code in playground)

---

Edit

Based on a comment by @Twois, who pointed out that it won't work when targetting es6, here's a version that will work:

class Base {
    public static getGetters(): string[] {
        return Reflect.ownKeys(this.prototype).filter(name => {
            return typeof Reflect.getOwnPropertyDescriptor(this.prototype, name)["get"] === "function";
        }) as string[];
    }

    public static getSetters(): string[] {
        return Reflect.ownKeys(this.prototype).filter(name => {
            return typeof Reflect.getOwnPropertyDescriptor(this.prototype, name)["set"] === "function";
        }) as string[];
    }
}

The main difference: using Reflect.ownKeys(this.prototype) instead of Object.keys(this.prototype).