This function calculates the average of all the numbers in an array.
JavaScript:
let average = arr => arr.reduce((acc, val) => acc + val, 0) / arr.length;
// Example
console.log(average([1, 2, 3, 4, 5])); // 3
console.log(average([10, 20, 30, 40])); // 25
TypeScript:
let average = (arr: number[]): number => arr.reduce((acc, val) => acc + val, 0) / arr.length;
// Example
console.log(average([1, 2, 3, 4, 5])); // 3
console.log(average([10, 20, 30, 40])); // 25