CODEWITHSUNDEEP
javascripthtmlforeachlabelcreateelement
Sterling Butters
Sterling Butters

Reputation: 1175

(Js) Label element creation undefined in loop

I have the following code in which I attempt to iteratively create label element newDay (to which I append newDayIcon and finally append to newWeekSet:

...
console.log(dict);

  var newLine = document.createElement('div').classList.add('list-group-item');
  var newButton = document.createElement('div').classList.add('add-button');
  var newTemp = document.createElement('a');
  var newName = document.createElement('a').classList.add('name-font');
  var newWeekSet = document.createElement('div').classList.add('right-align');
  Object.entries(dict).forEach(function([key, value]) {
     console.log(key, value);
     var newDay = document.createElement('label').classList.add('day-font');
     var newDayIcon;
     console.log(newDay);
     newDay.textContent = key.charAt(0);
     if (value) {
       newDayIcon = document.createElement('i').classList.add('far', 'fa-check-circle', 'fa-xs')
       newDayIcon.style.color = 'Blue';
     } 
     else {
       newDayIcon = document.createElement('i').classList.add('far', 'fa-times-circle', 'fa-xs')
       newDayIcon.style.color = 'Orange';
     }
     newDay.appendChild(newDayIcon);
     newWeekSet.appendChild(newDay);
  });
  var newMoveIcon = document.createElement('i').classList.add('fas', 'fa-bars');
  newButton.id = 'schedule-'+i++;

  newLine.append(newButton, newName, newWeekSet, newMoveIcon);
  dashboard.appendChild(newLine);
}

with the following current output:

  Friday: null,
  Monday: Object {
    EndTime: "12:50 A.M.",
    StartTime: "12:55 A.M."
  },
  Saturday: null,
  Sunday: Object {
    EndTime: "12:50 A.M.",
    StartTime: "12:55 A.M."
  },
  Thursday: null,
  Tuesday: null,
  Wednesday: null
}

"Sunday" Object {
  EndTime: "12:55 A.M.",
  StartTime: "12:59 A.M."
}

undefined

TypeError: undefined is not an object (evaluating 'newDay.textContent = key.charAt(0)')

I can't seem to figure out why newDay element can not be created in this way - is there a particular reason this won't work?

Upvotes: 0

Views: 192

Answers (1)

sdotson
sdotson

Reputation: 820

I think I see the issue. document.createElement('label').classList.add('day-font'); doesn't return a value. Anywhere you use the result of classList.add you're essentially assigning the var to undefined.

I see this pattern in many places in your script. I suggest creating the element and assigning the value to a var before you try to manipulate it like so: 

var newDay = document.createElement('label');
newDay.classList.add('day-font');
// do even more things to newDay if you want.

Anywhere where you create a new element and then try to update that element later, you'll want to split the steps apart like that.

Let me know if you have any questions!

Upvotes: 2

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