If clause with multiple conditions

I seem to be lost or just seem to be confused. To simplify the problem: I want to check whether each in an array holds true and if and only if all are true it should return a specific value.

var trueArray=[true,true,true,true];

As in my code, the array can have length up to 100 elements, I can't simply check for every element but need a for loop.

for(var i=0;i<trueArray.length;i++){
   if(trueArray[i]===true){
     //do something
  }
}

However, the above code does something on each step of the loop but I only want it to do something once every condition held true and not inbetween. Can't think of the solution at the moment