Question 233886 in Javascript Question posted in
A very good W3school tutorial can be found here.

Javascript sorting array day name

I’m going to sort day name based on array list day with below code:

var dayList = ['Mon', 'Fri', 'Sun', 'Wed', 'Sat'];

const map = {
   'Mon': 1,'Tue': 2,'Wed': 3,'Thu': 4,'Fri': 5,'Sat': 6, 'Sun': 7
};

dayList.sort((a, b) => {
   return map[a.day] - map[b.day];
});

console.log(dayList);

But it show me same sort result to :
[ "Mon", "Fri", "Sun", "Wed", "Sat"]

It should be like this:

[ "Mon", "Wed", "Fri", "Sat", "Sun"]

Any idea how to make it work?

Tags:

2

Answers


  1. 0

    You are trying to access day property from the elements in dayList which really does not exists and returns undefined.
    You should compare day names directly.

    Change:

    return map[a.day] - map[b.day];

    To:

    return map[a] - map[b];

    Code Example:

    var dayList = ['Mon', 'Fri', 'Sun', 'Wed', 'Sat'];

const map = {
   'Mon': 1,'Tue': 2,'Wed': 3,'Thu': 4,'Fri': 5,'Sat': 6, 'Sun': 7
};

dayList.sort((a, b) => {
   return map[a] - map[b];
});

console.log(dayList);
    Login or Signup to reply.
  2. 0

    It looks like there’s a small issue in your sorting function. The day property is not necessary since you’re directly comparing the day names from the dayList array.

     var dayList = ['Mon', 'Fri', 'Sun', 'Wed', 
         'Sat'];

  const map = {
 'Mon': 1, 'Tue': 2, 'Wed': 3, 'Thu': 4, 'Fri': 
  5, 'Sat': 6, 'Sun': 7
  };

 dayList.sort((a, b) => {
  return map[a] - map[b]; // Compare directly 
                           using day names
     });

 console.log(dayList);

    let me know if this can help you.

    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search