Refactored exercise codes to DRY up random input gen code

Author: tdd

exercises/async_loops/exercise.js

@@ -3,29 +3,23 @@
 var deepEqual = require('deep-eql')
 var inspect = require('util').inspect
 var loremIpsum = require('lorem-ipsum')
+var random = require('../randomizer')
 var runner = require('../../runner')
 
-function randomInt(min, max) {
-  return Math.floor((Math.random() * (max - min)) + min)
-}
-
 // All deepEqual impls (assert, deep-eql…) seem to b0rk when multiple objects
 // in an array share the same `id` value (wtf?!), so we make sure they're unique.
-var userCount = randomInt(10, 20)
+var userCount = random.int(10, 20)
 var userIds = []
 while (userIds.length < userCount) {
-  var id = randomInt(0, 1000)
+  var id = random.int(0, 1000)
   if (-1 !== userIds.indexOf(id)) continue
     userIds.push(id)
 }
 
-var users = Array.apply(null, { length: userCount }).map(function() {
+var users = random.arrayOf(userCount, function() {
   return {
     id: userIds.shift(),
-    name: loremIpsum().split(' ').slice(0, 2).map(function(word) {
-      word[0] = word[0].toUpperCase();
-      return word;
-    }).join(' ')
+    name: random.words(2, { capitalized: true })
   }
 })
 
@@ -41,7 +35,7 @@ module.exports = runner.custom(function(f) {
       var match = users.filter(function(user) {return user.id === id})
       if (match.length) fn(match[0])
       else fn(null)
-    }, Math.floor(Math.random() * 1000))
+    }, random.int(0, 1000))
   }
   var done = function(submittedUsers) {
     clearTimeout(tooLong)

exercises/basic_call/exercise.js

@@ -1,15 +1,10 @@
 "use strict"
 
+var random = require('../randomizer')
 var runner = require('../../runner')
 var util = require('util')
 
-function randomInt(min, max) {
-  return Math.floor((Math.random() * (max - min)) + min)
-}
-
-var input = Array.apply(null, { length: randomInt(0, 20) }).map(function() {
-  return randomInt(0, 10)
-})
+var input = random.arrayOfInts(20, 0, 10)
 
 module.exports = runner.custom(function(fx, numbers) {
   var valid = 1

exercises/basic_every_some/exercise.js

@@ -1,34 +1,27 @@
 "use strict"
 
-var loremIpsum = require('lorem-ipsum')
+var random = require('../randomizer')
 var runner = require('../../runner')
 
-function randomInt(min, max) {
-  return Math.floor((Math.random() * (max - min)) + min)
-}
-
 function makeUser() {
   return {
-    id: randomInt(0, 1000),
-    name: loremIpsum().split(' ').slice(0, 2).map(function(word) {
-      word[0] = word[0].toUpperCase();
-      return word;
-    }).join(' ')
+    id: random.int(0, 1000),
+    name: random.words(2, { capitalized: true })
   }
 }
 
 function makeListOfUsers() {
-  return Array.apply(null, { length : randomInt(10, 100) }).map(makeUser)
+  return random.arrayOf(10, 100, makeUser)
 }
 
 var good = makeListOfUsers()
 var bad = makeListOfUsers()
-var lists = Array.apply(null, {length: 20}).map(function() {
-  return Array.apply(null, {length: 20}).map(function() {
+var lists = random.arrayOf(20, function() {
+  return random.arrayOf(20, function() {
     if (Math.random() < 0.95) {
-      return good[randomInt(0, 10)]
+      return good[random.int(0, 10)]
     } else {
-      return bad[randomInt(0, 10)]
+      return bad[random.int(0, 10)]
     }
   })
 })

exercises/basic_filter/exercise.js

@@ -1,13 +1,11 @@
 "use strict"
 
 var loremIpsum = require('lorem-ipsum')
+var random = require('../randomizer')
 var runner = require('../../runner')
 
-function randomInt(min, max) {
-  return Math.floor((Math.random() * (max - min)) + min)
-}
-
-var input = new Array(randomInt(10, 30)).join(',').split(',')
-  .map(function() { return { message: loremIpsum() } })
+var input = random.arrayOf(10, 30, function() {
+  return { message: loremIpsum() }
+})
 
 module.exports = runner.hideInput(input)

exercises/basic_map/exercise.js

@@ -1,13 +1,9 @@
 "use strict"
 
+var random = require('../randomizer')
 var runner = require('../../runner')
 
-function randomInt(min, max) {
-  return Math.floor((Math.random() * (max - min)) + min)
-}
-
-var input = new Array(randomInt(0, 19)).join(',').split(',')
-  .map(function() { return randomInt(0, 9) })
+var input = random.arrayOfInts(19, 0, 9)
 
 var regularMap = Array.prototype.map, usedMap
 Array.prototype.map = function() {

exercises/higher_order_functions/exercise.js

@@ -1,16 +1,13 @@
 "use strict"
 
+var random = require('../randomizer')
 var runner = require('../../runner')
 
-function randomInt(min, max) {
-  return Math.floor((Math.random() * (max - min)) + min)
-}
-
 var counter
 
 module.exports = runner.init(function() {
   console.log("------------------------")
   counter = 0
 }).quiet(function count() {
   console.log("Called function %d times.", ++counter)
-}, randomInt(3, 10))
+}, random.int(3, 10))

exercises/partial_application_without_bind/exercise.js

@@ -1,11 +1,10 @@
 "use strict"
 
 var loremIpsum = require('lorem-ipsum')
+var random = require('../randomizer')
 var runner = require('../../runner')
 
-var input = Array.apply(null, {length: Math.random() * 20 + 1}).map(function() {
-  return loremIpsum()
-})
+var input = random.arrayOfLorems(1, 20)
 
 // FIXME: THIS DOES NOT CAPTURE console.log OUTPUT PROPERLY (as it happens
 // inside the runner, not in child processes).  WE NEED TO CHANGE THIS INTO

exercises/randomizer.js

@@ -0,0 +1,49 @@
+"use strict"
+
+var loremIpsum = require('lorem-ipsum')
+
+function randomArrayOf(minCells, maxCells, callback) {
+  if ('function' === typeof maxCells && 'undefined' === typeof callback) {
+    callback = maxCells
+    maxCells = minCells
+  }
+  return Array.apply(null, { length: randomInt(minCells, maxCells) }).map(callback)
+}
+
+function randomArrayOfInts(maxCells, minInt, maxInt) {
+  return randomArrayOf(0, maxCells, function() {
+    return randomInt(minInt, maxInt)
+  })
+}
+
+function randomArrayOfLorems(minCells, maxCells) {
+  var loremOptions = Array.prototype.slice(arguments, 2)
+  return randomArrayOf(minCells, maxCells, function() {
+    return loremIpsum.apply(loremIpsum, loremOptions)
+  })
+}
+
+function randomInt(min, max) {
+  if (min === max) return max
+  return Math.floor((Math.random() * (max - min + 1)) + min)
+}
+
+function randomWords(count, options) {
+  options = options || {}
+  var result = loremIpsum().split(' ').slice(0, count)
+  if (options.capitalized) {
+    result = result.map(function(word) {
+      word[0] = word[0].toUpperCase()
+      return word
+    })
+  }
+  return result.join(' ')
+}
+
+module.exports = {
+  int: randomInt,
+  arrayOf: randomArrayOf,
+  arrayOfInts: randomArrayOfInts,
+  arrayOfLorems: randomArrayOfLorems,
+  words: randomWords
+}

exercises/recursion/exercise.js

@@ -1,11 +1,8 @@
 "use strict"
 
+var random = require('../randomizer')
 var runner = require('../../runner')
 
-function randomInt(min, max) {
-  return Math.floor((Math.random() * (max - min)) + min)
-}
-
 var data = {
   "name": "functional-javascript-workshop",
   "version": "0.0.13",
@@ -105,7 +102,7 @@ var data = {
 }
 
 function getRandomSubTree() {
-  return randomInt(0, Object.keys(data.dependencies.workshopper.dependencies).length)
+  return random.int(0, Object.keys(data.dependencies.workshopper.dependencies).length)
 }
 
 var items = [getRandomSubTree(), getRandomSubTree(), getRandomSubTree(), getRandomSubTree()]

exercises/recursion/solution/solution.js

@@ -1,6 +1,6 @@
 function getDependencies(mod, result) {
   result = result || []
-  var dependencies = mod.dependencies || []
+  var dependencies = mod && mod.dependencies || []
   Object.keys(dependencies).forEach(function(dep) {
     var key = dep + '@' + mod.dependencies[dep].version
     if (result.indexOf(key) === -1) result.push(key)