moy-fp/src/List/transpose.js

A functional programming library.

import curry from '../Function/curry'

/**
 * [[a]] -> [[a]]
 */
const transpose = curry(
  list => {
    const result = []
    for(let innerList of list){
      const innerEntries = innerList.entries()
      for(let [index, item] of innerEntries){
        if(!result[index]){
          result[index] = []
        }
        result[index].push(item)
      }
    }
    return result
  }
)

export default transpose