Array Guide

// Is x really array?
Array.isArray(x)

// Add array y to the end of x
x.concat(y)

// Is y in x?
x.includes(y)

// Which index is y?
x.indexOf(y)

// Insert item at end
x.push(y)

// Insert item at index
x.splice(index, 0, y)

// Replace item at index
x.splice(index, 1, y)

// Remove last item
x.pop()

// Remove first item
x.shift()

// Remove items
x.slice(2) //first 2 items
x.slice(2, 4) // first 2 and 4

// MAP - Edit everything
x.map(y => y * 2);

// Reverse order
x.reverse()

// Alphabetical order (strings)
x.sort()

// Convert to string
x.toString()