Typescript property does not exist on type {}

I have the following code in Typescript. Why does the compiler throws an error?

var object = {};
Object.defineProperty(object, 'first', {
     value: 37,
     writable: false,
     enumerable: true,
     configurable: true
});
console.log('first property: ' + object.first);

js.ts(14,42): error TS2339: Property 'first' does not exist on type '{}'.

It's the same code snippet like in the documentation of mozilla (examples section).

Solution 1:

Make the object type any:

var object: any = {};

Solution 2:

Another way is to do interface, so compiler will know that property exists.

interface IFirst{
  first:number;
}


let object = {} as IFirst;
Object.defineProperty(object, 'first', {
  value: 37,
  writable: false,
  enumerable: true,
  configurable: true
});
console.log('first property: ' + object.first);

Take a look at this question How to customize properties in TypeScript