type-checked property name string literals - https://www.typescriptlang.org/play?#code/PTAEEsDsGcAdwE4FMAmoBGBPUALALnrNAFwjQDGOkS4KSk6AhpQHQDm4e6A9twNbQW4bsDyZYSCgnCw8AWnK8+PfsEWQ89PMEiMAtkm4AzOdwkJGebghb49AGwBQj4ACpXoAKIwArslB4OEig0HjSkGygAG6M9j7B4NCgjNGxtKCwCGZICGKgugagxgHiwQAGACploK7AjkY+kOR4wpAZWbAAcvpIADwVAHwAFAVIxKB8SJjFFQCU46HhkQDejqDroMh…

ts-propertyOf.ts

// inspired by https://schneidenbach.gitbooks.io/typescript-cookbook/content/nameof-operator.html

/** Ensure the string value is a valid property name of type `T` */
function propName<T>(name: keyof T): string {
    return name.toString();
}

/** Ensure the string value is a valid property name of instance of type `T`. */
function propOf<T>(instance: T, name: keyof T): string {
    return propName<T>(name);
}

interface MultimediaDirectory {
    name: string;
    path: string;
}

const compiles1 = propName<MultimediaDirectory>('name');
const fails1 = propName<MultimediaDirectory>('nameddd');


const instance: MultimediaDirectory = {
    name: 'My Documents',
    path: 'C:\\My Documents'
};

const compiles2 = propOf(instance, 'name');
const fails2 = propOf(instance, 'wrong');