export function validateArgs(constructor: Function) {
  // copy the methods so that we avoid self referencing.
  const original: Function = Object.assign({}, constructor);
  // iterate over all the static methods in the class
  for (const i in constructor) {
    // wrap them in a method that throws an error if args are not valid
    constructor[i] = function(...args: any[]) {
      if(areArgsValid(args)) {
           return original[i].apply(this, args);
      }
      throw `Args aren't valid`
    };
  }
}

@validateArgs
class Validator {
    static myThingIsValid(arg1) {
         return !!arg1;
    }
    myOtherThingIsValid(arg1) {
         return !!arg1;
    }
}

for (const i in constructor) { ... }

Object.getOwnPropertyNames(constructor)
    .filter(prop => typeof prop === 'function')
    .forEach(val => ...)

[
    ...Object.getOwnPropertyNames(constructor),
    ...Object.getOwnPropertyNames(constructor.prototype)
]
.filter(prop => typeof prop === 'function')
.forEach(val => ...)