moy-fp/src/Functor/map.js

A functional programming library.

import curry from '../Function/curry'

/**
 * Functor f => (a -> b) -> f a -> f b
 */
const map = curry(
  (fn, F) => {
    if(Object.prototype.toString.call(F) === '[object Array]'){
      const list = []
      for(let item of F){
        list.push(fn(item))
      }
      return list
    }
    return F.map(fn)
  }
)

export default map