Remove duplicate values in an array
JavaScript version
const removeDuplicate = (arr) => arr.filter((i) => arr.indexOf(i) === arr.lastIndexOf(i));
TypeScript version
const removeDuplicate = <T,_>(arr: T[]): T[] => arr.filter((i) => arr.indexOf(i) === arr.lastIndexOf(i));
Example
removeDuplicate(['h', 'e', 'l', 'l', 'o', 'w', 'o', 'r', 'l', 'd']); // ['h', 'e', 'w', 'r', 'd']