Swap two array items

JavaScript version

// `i` must be less than `j`
const swapItems = (a, i, j) => (a[i] && a[j] && [...a.slice(0, i), a[j], ...a.slice(i + 1, j), a[i], ...a.slice(j + 1)]) || a;

TypeScript version

const swapItems = <T,_>(a: T[], i: number, j: number): T[] => (a[i] && a[j] && [...a.slice(0, i), a[j], ...a.slice(i + 1, j), a[i], ...a.slice(j + 1)]) || a;

Example

swapItems([1, 2, 3, 4, 5], 1, 4); // [1, 5, 3, 4, 2]