helper to extract functions from prototypes

decouple-methods.js

const decoupleMethods = (Type, ...names) => names.map(
  name => ({ [name]: (a, b) => Type.prototype[name].call(b, a) }) // could be curried
).reduce((acc, next) => Object.assign({}, acc, next))

const { map, filter, forEach, find } = decoupleMethods(
  Array,
  'map',
  'filter',
  'forEach',
  'find'
)

find(n => n === 1, [4, 3, 2, 1]) // 1