I am using underscore to sort an array. Is there a way to make nulls always last whether ascending or descending? For example:

[
    { name: 'a', age: 1 }, 
    { name: 'z', age: 5 }, 
    { name: '', age: 1 }, 
    { name: 'v', age: 7 }
]

Will produce

[
    { name: 'a', age: 1 }, 
    { name: 'v', age: 7 }, 
    { name: 'z', age: 5 }, 
    { name: '', age: 1 }
]

and descending will produce:

[
    { name: 'z', age: 5 }, 
    { name: 'v', age: 7 }, 
    { name: 'a', age: 1 }, 
    { name: '', age: 1 }
]

My real array is an array of objects so i have to pluck values out.

I am using underscore to sort an array. Is there a way to make nulls always last whether ascending or descending? For example:

[
    { name: 'a', age: 1 }, 
    { name: 'z', age: 5 }, 
    { name: '', age: 1 }, 
    { name: 'v', age: 7 }
]

Will produce

[
    { name: 'a', age: 1 }, 
    { name: 'v', age: 7 }, 
    { name: 'z', age: 5 }, 
    { name: '', age: 1 }
]

and descending will produce:

[
    { name: 'z', age: 5 }, 
    { name: 'v', age: 7 }, 
    { name: 'a', age: 1 }, 
    { name: '', age: 1 }
]

My real array is an array of objects so i have to pluck values out.

• javascript
• underscore.js

• You can remove all the null values, why put them on the end? – Bazinga Commented Nov 23, 2014 at 20:18
• I am trying to sort a property on an object. So even if a property is null the other properties are useful. – Luke101 Commented Nov 23, 2014 at 20:22
• You can make a plunker so i can try to help you? – Bazinga Commented Nov 23, 2014 at 20:24
• Why do you need to do this? – istos Commented Nov 23, 2014 at 20:25
• I am trying to mimick a database "order by Name NULLS LAST" – Luke101 Commented Nov 23, 2014 at 20:27

3 Answers 3

There are many ways to go about it but you could try something like this:

var arr = [{name: 'a', age: 1}, {name: 'z', age: 5}, {name: '', age: 1}, {name: 'v', age: 7 }];

_.chain(arr)
 .sortBy('name')
 //.reverse() // to sort descending
 .partition('name')
 .flatten()
 .value();

Result:

[ { name: 'a', age: 1 },
  { name: 'v', age: 7 },
  { name: 'z', age: 5 },
  { name: '', age: 1 } ]

You could simply find them after sorting and put them in the back manually. Maybe by splitting the different values in 2 arrays and then concatenating them. One of the arrays contains non null values and the other the null values

You can do this with lodash, and im think underscore as this function too.

var users =[{name: 'a', age: 1}, {name: '', age: 4}, {name: 'z', age: 5}, {name: '', age: 1}, {name: 'v', age: 7 }];

_.sortBy(users, 'name');

The results will give you the null names in the beginning:

[{name: '', age: 1}, {name: '', age: 4}, {name: 'a', age: 1}, {name: 'z', age: 5}, {name: 'v', age: 7 }];