_.flow does not preserve initial function arity #3612
Description
Using flow does not preserve the arity of the first function passed in, so _.curry won't work and you need to use _.curryN.
let add = (x, y) => x + y
let double = x => x * 2
// Returns 10
_.flow(add, double)(1, 4)
// Throws Exception
_.curry(_.flow(add, double))(1)(4)
// Returns 10
_.curryN(2, _.flow(add, double))(1)(4)More specifically this is 0:
_.flow(add, double).lengthI've worked around this by defining a combo flow/curry function (forgive the silly name 😄 ):
let flurry = (...fns) => _.curryN(fns[0].length, _.flow(...fns))This seems like a bug in _.flow.