Function dedup

Removes consecutive doubles. If no argument is provided, standard !== will be used to compare both values. If a mapping fn is provided, the result of the mapping fn will be compared using !==, which means the mapping function should produce a 'simple' types like number or string.

(The alternative option would have been to pass 2 arguments to the compare fn and if it returns true, the elements would be considered equal)

Example

   pipe(
     itr8.itr8FromArrayAsync([ 1, 2, 2, 2, 3, 4, 4, 3 ]),
     itr8.dedup(), // => [ 1, 2, 3, 4, 3 ]
   );

Example

   pipe(
     itr8.itr8FromArrayAsync([ { id: 1 }, { id: 2 }, { id: 2 }, { id: 3 }, { id: 4 }, { id: 4 }, { id: 3 } ])
     itr8.dedup((a:{ id:number }) => id ) // => [ [ { id: 1 }, { id: 2 }, { id: 3 }, { id: 4 }, { id: 3 } ];
   );