Arrays

Ordered, zero-indexed lists of values.

Creating & indexing

const nums = [10, 20, 30];
nums[0];        // 10
nums.length;    // 3
nums.push(40);  // [10, 20, 30, 40]

Common methods

const doubled = nums.map((n) => n * 2);
const evens   = nums.filter((n) => n % 2 === 0);
const total   = nums.reduce((sum, n) => sum + n, 0);

Iterating

for (const n of nums) {
  console.log(n);
}