es5-workshop/exercises/array-reduce/solution.js

NodeSchool ES5 Workshop

function countWords(arr) {
  return arr.reduce(function(countMap, word) {
    countMap[word] = ++countMap[word] || 1 // increment or initialize to 1
    return countMap
  }, {}) // second argument to reduce initialises countMap to {}
}

module.exports = countWords