composeV

Composes variadic functions (n-ary). composeV handles unary functions the same as compose ((x) -> (x) -> (x)) -> (x), but can also handle miss-matched arities ((x, y), (x), (x, y, z), ...) -> (x, y, z, ...). Composed functions are nested in parameters[0] while the remaining arguments are passed to parameters[1...]. This can be useful when you need to compose functions while still being able to pass the same arguments into each successive function unchanged.

Note: composeV is non-curried (compose isn't typically). Be sure to reference ramda or a comparable library to make sure there isn't a better fit out there for your particular use-case.

Install

$ npm install --save compose-v

Usage

const composeV = require('compose-v')

// Compose unary functions
const x = x => x + x
const y = x => x * x
const xy = composeV(y, x) // xy :: (a) -> y(x(a))
xy(5) // 100 OR (5 + 5) * 10

// Compose two binary functions
const x = (x, y) => x + y
const y = (x, y) => x * y
const xy = composeV(y, x) // xy :: (a, b) -> y(x(a, b), b)
xy(5, 5) // 50 OR (5 + 5) * 5

// Compose miss-matched n-ary functions
// (Must pass maximum arguments, in this case 3)
const x = (x, y) => x + y
const y = (x, y, z) => x * y * z
const xy = composeV(y, x) // xy :: (a, b, c) -> y(x(a, b, c), b, c)
xy(4, 6, 8) // 24 OR 4 + 6 + 6 + 8

License

MIT © Rob LaFeve