.reduce method
Summ numbers
const numbers: number[] = [1, 2, 3, 6, 30];
const sum: number = numbers.reduce((acc, curr) => acc + curr, 0);
console.log(sum); // Output: 42
Flattening Arrays
const nestedArray: number[][] = [[1, 2], [3, 4], [5, 6]];
const flattenedArray: number[] = nestedArray.reduce((acc, curr) => acc.concat(curr), []);
console.log(flattenedArray); // Output: [1, 2, 3, 4, 5, 6]