JavaScript version
mul.js
const mul = (...args) => args.reduce((a, b) => a * b);TypeScript version
mul.ts
const mul = (...args: number[]): number => args.reduce((a, b) => a * b);Examples
examples.js
mul(1, 2, 3, 4); // 24const mul = (...args) => args.reduce((a, b) => a * b);const mul = (...args: number[]): number => args.reduce((a, b) => a * b);mul(1, 2, 3, 4); // 24