dist/script/prelude/array.js
function groupOn(f, xs) {
    return groupBy((a, b) => f(a) === f(b), xs);
}
function groupOn(f, xs) {
    return groupBy((a, b) => f(a) === f(b), xs);
}
function groupOn ( f , xs ) { return groupBy ( ( a , b ) => f ( a ) === f ( b ) , xs ) ; }
Splits an array based on the equivalence relation induced by the function.
The concatenation of the result is equal to the argument.
Splits an array based on the equivalence relation induced by the function . The concatenation of the result is equal to the argument .