Move done tasks to end

script

// Completed items moved to bottom of draft
(() => {

   // main :: () -> IO Bool
   const main = () => {

       // completedItemsToEnd :: Draft -> String
       const completedItemsToEnd = d =>
           concat( // Two lists rejoined,
               partition( // after partition.
                   d.languageGrammar === 'Taskpaper' ? (
                       x => !x.includes('@done')
                   ) : x => !/^\s*-\s*\[[x\-\*\+]\]/.exec(x),
                   d.content.split('\n')
               )
           ).join('\n');

       draft.content = (
           completedItemsToEnd(draft)
       );
       draft.update();

       console.log(true);
       return true;
   };

   // General reusable helper functions ------------------

   // concat :: [[a]] -> [a]
   // concat :: [String] -> String
   const concat = xs =>
       xs.length > 0 ? (() => {
           const unit = typeof xs[0] === 'string' ? '' : [];
           return unit.concat.apply(unit, xs);
       })() : [];

   // partition :: Predicate -> List -> (Matches, nonMatches)
   // partition :: (a -> Bool) -> [a] -> ([a], [a])
   const partition = (p, xs) =>
       xs.reduce(
           (a, x) =>
           p(x) ? (
               [a[0].concat(x), a[1]]
           ) : [a[0], a[1].concat(x)], [
               [],
               []
           ]
       );

   // MAIN -----------------------------------------------
   return main();
})();