Mastering JavaScript's Array Powerhouses: forEach, map, filter, reduce, spread, and rest

JavaScript arrays are incredibly powerful, especially when you master methods like forEach, map, filter, reduce, and the spread and rest operators. In this article, we'll break down what each does and provide practical examples.

forEach

Use forEach to iterate over each item in an array:

const arr = [1,2,3];
arr.forEach(item => console.log(item));

map

Use map to transform each item and return a new array:

const doubled = arr.map(item => item * 2);

filter

Use filter to keep only items that match a condition:

const evens = arr.filter(item => item % 2 === 0);

reduce

Use reduce to aggregate array values:

const sum = arr.reduce((acc, item) => acc + item, 0);

Spread & Rest

The spread operator (...) expands arrays:

const arr2 = [...arr, 4, 5];

The rest operator (...) collects function arguments:

function sumAll(...nums) {
      return nums.reduce((a, b) => a + b, 0);
    }

Master these and you'll handle arrays like a pro!