array_to_nested_hash.rb

window.CO2M ||= {}
window.CO2M.UTIL =
  _defineProperty: (obj, key, value) ->
    if key of obj
      Object.defineProperty obj, key,
        value: value
        enumerable: true
        configurable: true
        writable: true
    else
      obj[key] = value
    obj

  arrayToNestedHash: (arr) ->
    last_element = true
    reducer = (acc, item) ->
      if last_element
        last_element = false
        item
      else
        CO2M.UTIL._defineProperty {}, item, acc

    arr.reduceRight reducer, {}