Question

I have an array of div names (with no hash), and i’m using the following jQuery code do do something with them:

for(dayList in dayLists) {
  dayListID = "#" + dayList;
  $(dayListID).append("test");
}

Unfortunately, it does not work. I can see in the console that dayListID is an “HTMLDivElement”, rather than the string that JQ is expecting. How can I join a hash and the div name while keeping the result as a string? Thanks!

Answer 1

Try this:

for(dayList in dayLists) {
  dayListID = "#" + dayLists[dayList];
  $(dayListID).append("test");
}

dayList in for .. in is not a i-th value of the dayLists, but it is the index. So for array ["one", "two"] variable dayList is 0, 1 and to get the values you must use dayLists[dayList].

As Matt wrote in the comments it is good to use hasOwnProperty to make sure the properties we are looping through are the objects own.

for(dayList in dayLists) {
  if(dayLists.hasOwnProperty(dayList) {
    dayListID = "#" + dayLists[dayList];
    $(dayListID).append("test");
  }
}

… and then you realize the standard simple for loop (answer by MДΓΓ БДLL) is actually a better idea. The standard for is also faster.

See details HERE.