moy-fp/src/Object/assocPath.js

A functional programming library.

import curry from '../Function/curry'
import update from '../List/update'
import assoc from './assoc'

/**
 * [k] -> v -> {k: v} -> {k: v}
 */
const assocPath = curry(
  (paths, value, obj) => {
    const key = paths[0],
          length = paths.length
    return length === 0 ? 
            obj :
            length === 1 ? 
              Number.isInteger(key) ? 
                update(key, value, obj) : 
                assoc(key, value, obj) : 
              Number.isInteger(key) ?
                update(key, assocPath(paths.slice(1), value, obj !== null && typeof obj === 'object' && Object.hasOwnProperty.call(obj, key) ? obj[key] : []), obj) :
                assoc(key, assocPath(paths.slice(1), value, obj !== null && typeof obj === 'object' && Object.hasOwnProperty.call(obj, key) ? obj[key] : {}), obj)
  }
)

export default assocPath