xen-orchestra/@vates/compose/.USAGE.md

import { compose } from '@vates/compose'

const add2 = x => x + 2
const mul3 = x => x * 3

// const f = x => mul3(add2(x))
const f = compose(add2, mul3)

console.log(f(5))
// → 21

The call context (this) of the composed function is forwarded to all functions.

The first function is called with all arguments of the composed function:

const add = (x, y) => x + y
const mul3 = x => x * 3

// const f = (x, y) => mul3(add(x, y))
const f = compose(add, mul3)

console.log(f(4, 5))
// → 27

Functions may also be passed in an array:

const f = compose([add2, mul3])

Options can be passed as first parameter:

const f = compose(
  {
    // compose async functions
    async: true,

    // compose from right to left
    right: true,
  },
  [add2, mul3]
)

Functions can receive extra parameters:

const isIn = (value, min, max) => min <= value && value <= max

// Only compatible when `fns` is passed as an array!
const f = compose([
  [add, 2],
  [isIn, 3, 10],
])

console.log(f(1))
// → true

Note: if the first function is defined with extra parameters, it will only receive the first value passed to the composed function, instead of all the parameters.