String Reordering.js

/*
Description:
The input will be an array of dictionaries.

Return the values as a string-seperated sentence in the order of their keys' integer equivalent (increasing order).

The keys are not reoccurring and their range is -999 < key < 999. The dictionaries' keys & values will always be strings and will always not be empty.

Example
Input:
List = [
        {'4': 'dog' }, {'2': 'took'}, {'3': 'his'},
        {'-2': 'Vatsan'}, {'5': 'for'}, {'6': 'a'}, {'12': 'spin'}
       ]

Output:
'Vatsan took his dog for a spin'
*/
const sentence = list => (
  list
    .sort((a, b) => Object.keys(a)[0] - Object.keys(b)[0])
    .map(obj => Object.values(obj)[0])
    .join(' ')
);