Sorting helpers in TypeScript

typescript-sorting-helpers.ts

type SortingFunction<T = any> = (a: T, b: T) => number;

/**
 * Accepts a key, returns an ascending sorting function for that key
 */
const ascending = <T = any>(key: keyof T): SortingFunction<T> => {
 return (a: any, b: any) => {
  const aValue = a[key];
  const bValue = b[key];
  return (aValue === bValue) ? 0 : (aValue < bValue ? -1 : 1);
 };
};

/**
 * Accepts a key, returns a descending sorting function for that key
 */
const descending = <T = any>(key: keyof T): SortingFunction<T> => {
 return (a: T, b: T) => {
  const aValue = a[key];
  const bValue = b[key];
  return (aValue === bValue) ? 0 : (aValue > bValue ? -1 : 1);
 };
};

// Try it out
const arr = [
    { foo: 22 },
    { foo: 11 },
    { foo: 33 },
];

console.log('Ascending');
console.log(arr.sort(ascending('foo')));
console.log('Descending');
console.log(arr.sort(descending('foo')));