Array orderBy by properties in array type

orderby.extension.ts

type FlattenIfArray<T> = T extends (infer R)[] ? R : T;

interface Array<T> {
    orderBy<K extends keyof FlattenIfArray<T>>(key: K): Array<any>;
}

Array.prototype.orderBy = function<K>(key: K): Array<any> {
   return this.sort((a: any, b: any) => a[key] - b[key]);
}

interface Test {
    test1: string
}
let array: Array<Test> = [{test1: '14'},{test1: '3'}, {test1: '97'}, {test1: '1'}];
console.table(array);
console.table(array.orderBy('test1'));