small ramda helpers

new_gist_file.js

const argsToArray = unapply(identity);

argsToArray(1, 3, 5); //-> [1, 3, 5]

////////////////////////////////////////////////////////////////


const dropArgs = curryN(2, compose(
  apply(drop),
  splitAt(1),
  argsToArray
));

dropArgs(2)('a', 'b', 'c', 'd'); //-> ["c", "d"]

////////////////////////////////////////////////////////////////


const dropArgsLast = curryN(2, compose(
  apply(dropLast),
  splitAt(1),
  argsToArray
));

dropArgsLast(2)('a', 'b', 'c', 'd'); //-> ["a", "b"]

////////////////////////////////////////////////////////////////


const takeArgs = curryN(2, compose(
  apply(take),
  splitAt(1),
  argsToArray
));

takeArgs(2)('a', 'b', 'c', 'd'); //-> ["a", "b"]

////////////////////////////////////////////////////////////////


const splice = converge(insertAll, [
  identity,
  nthArg(3),
  remove
]);

splice(1, 2, ['a', 'b', 'c', 'd', 'e'], ['add1', 'add2', 'add3']); //-> ["a", "add1", "add2", "add3", "d", "e"]

////////////////////////////////////////////////////////////////


const sliceByCount = converge(slice, [identity, add, nthArg(2)]);

sliceByCount(1, 3, ['a', 'b', 'c', 'd', 'e']); //-> ["b", "c", "d"]

////////////////////////////////////////////////////////////////


const reverseElems = converge(insertAll, [
  identity,
  compose(reverse, sliceByCount),
  remove
]);

reverseElems(1, 3, ['a', 'b', 'c', 'd', 'e']) //-> ["a", "d", "c", "b", "e"]

////////////////////////////////////////////////////////////////


const reverseArgs = converge(compose, [
  compose(apply, nthArg(2)),
  compose(apply(reverseElems), takeArgs(2)),
  always(argsToArray)
])

reverseArgs(1, 3, argsToArray)('a', 'b', 'c', 'd', 'e') //-> ["a", "d", "c", "b", "e"]

////////////////////////////////////////////////////////////////


const repeatEl = converge(
  converge(splice, [
    identity,
    always(1),
    nthArg(2),
    converge(repeat, [nthArg(1), nthArg(3)])
  ]), [
    identity,
    converge(prop, [identity, nthArg(2)]),
    nthArg(2),
    nthArg(1)
  ]
)

repeatEl(1, 3, [5, 7, 12]); //-> [5, 7, 7, 7, 12]

////////////////////////////////////////////////////////////////


const repeatArg = converge(
  compose, [
    compose(apply, nthArg(2)),
    compose(apply(repeatEl), takeArgs(2)),
    always(argsToArray)
  ]);

const fn = argsToArray;
repeatArg(1, 3, fn)('a', 'b', 'c', 'd'); //-> ["a", "b", "b", "b", "c", "d"]