Quick Intro to Arrays in JavaScript


  • get first item in an array: array[0]
  • get last item in an array: array[array.length-1]
  • add item to end: array.push(val) can push multiple values
  • add item to beginning: array.unshift(val)
  • remove item from end: array.pop() returns the last item from an array and removes it
  • remove item from start: array.shift() returns the first item from an array and removes it
  • Join elements in an array: .join()
  • Join two Arrays: .concat()
  • Search arrays: indexOf()

Loops for Arrays

for( var i=0; i<arr.length; i += 1) {

Do note that using for loops are the ancient way of doing things. You should be using cool higher order functions like .map and .reduce