I don't know what it's called but I need help with it

yea you get it lol

INTERNECION Disrespectful??? nah bro went to far

Do you understand. it is 12:00 AM I am not dealing with this

Mellow
imma kill two birds with one stone on this
varrience probably has a better way but...

so anyways here how to for loop

for(var i = 0; i < 5; i++){
}

1. the var i = 0 means your making a variable called i which starts at 0
2. the i < 5 means the loop keeps repeating while i is less than 5
3. the i++ means i increases by one every time the loop repeats
   SO, in total, the loop repeats five times.
   now, to incorporate with arrays:
   for(var i = 0; i < array.length; i++){
}
   you'll notice its the same as before, except for part two where it now says i < array.length instead of i < 5
   this means that the for loop repeats array.length times, which means it repeats once for each object/achievement in the array

so now we can go through each achievement in the array by using array[i](the ith object in the array, and since i is changing once for each object in the array, we cover all the objects)
to sum it up you'd need something like this:
var numCompleted = 0;
for(var i = 0; i < achievements.length; i++){
if(achievements[i].completed === true){
numCompleted += 1;
}
}
again, hope this helps and im sure varrience has a better way of doing this but until then your welcome

Mellow possibly... not sure exactly what your trying to do, but i'll give 2 examples to try and answer what your trying to do, the

• first is to add a property that keeps track of that in the object that will update manually, unlike arrays objects don't have a .prototype.length attribute

• second is to encase multiple arrays of objects containing a Boolean on if they have been unlocked
  the two examples will be showcased below for those who want to learn

  var  obj = {
  pro: true,
  noob: false,
  achivements: 1
  total: 15
  }
  // we can then update it at any time a new achievement is unlocked
  var loser = true;
  if(loser && !obj.noob){obj.noob = true; achivements++}
  console.log("you have "+obj.total-obj.achivements+" left keep it up!")
  // the second way is below here which is basically what Ack did
  var accomp = [
  {title: "Ruiner", unlocked: false}
  {title: "Participation Award", unlocked: false}
  {title: "Secret Customer", unlocked: true}
  ];
  // to calculate how many achievements we have left we must iterate through the Array
  function accompLeft(){
  var left = accomp.length; // stores total achievements
  for(var i = 0; i < accomp.length; i++){
  if(accomp[i].unlocked){left--} // here we access an accomp [ index ] and a .property from that index 
  }
  return(left)
  } 

just stop f@cking arguing all the time goddammit
i am not going throught 48 posts >:(