如何以唯一的顺序对数组进行排序

Question

Given an array:

var myList = [ 'Normal', 'Urgent', 'Alert', 'Casual', 'Follow up' ];

I want to output this list in say, a dropdown. I want ' Urgent ' to show up first, followed by ' Alert '. The rest should be sorted alphabetically.

I'm aware I can alphabetically sort the entire array with myList.sort() but is there a way to sort this list to my unique requirements? I'm hoping this can be done as an array without converting it to an object and assigning priority identifiers - but I may be wrong.

Also, what if Urgent or Alert doesn't exist?

EDIT : Here is what I tried: https://jsfiddle.net/reala/rqacrz0k/

Answer 1

It's best if you keep your prioritized elements separate from the main list, if you can't guarantee they will be present. I would filter those elements out, sort the rest, and concatenate the results with your special list.

 var special = ["Urgent","Alert"]; var myList = [ 'Normal', 'Urgent', 'Alert', 'Casual', 'Follow up' ]; myList = special.concat(myList.filter(function(el){ return special.indexOf(el) == -1; }).sort()); alert(myList); 

Answer 2

You could use an object for the sort order.

 var array = [ 'Normal', 'Urgent', 'Alert', 'Casual', 'Follow up' ]; array.sort(function (a, b) { var order = { Urgent: -2, Alert: -1 }; return (order[a] || 0) - (order[b] || 0) || a.localeCompare(b); }); console.log(array); 

Answer 3

You could use filter to get the special values, sort the rest, and concatenate the parts:

 var myList = [ 'Normal', 'Urgent', 'Alert', 'Casual', 'Follow up' ]; myList = myList.filter( v => v === 'Urgent' ).concat( myList.filter( v => v === 'Alert' ), myList.filter( v => !['Alert','Urgent'].includes(v) ).sort()); console.log(myList); 

Answer 4

 var myList = [ 'Normal', 'Urgent', 'Alert', 'Casual', 'Follow up' ]; console.log(['Urgent', 'Alert', ...myList.filter(item => item !== 'Urgent' && item !== 'Alert').sort()]);