refactor: adjust randomDrop to use wrapped random function

test/common/fns/randomDrop.test.js

@@ -16,17 +16,14 @@ describe('common.fns.randomDrop', () => {
     user = generateUser();
     user._tmp = user._tmp ? user._tmp : {};
     task = generateTodo({ userId: user._id });
-    predictableRandom = () => {
-      return 0.5;
-    };
+    predictableRandom = sandbox.stub().returns(0.5);
   });
 
   it('drops an item for the user.party.quest.progress', () => {
     expect(user.party.quest.progress.collectedItems).to.eql(0);
     user.party.quest.key = 'vice2';
-    predictableRandom = () => {
-      return 0.0001;
-    };
+    predictableRandom.returns(0.0001);
+
     randomDrop(user, { task, predictableRandom });
     expect(user.party.quest.progress.collectedItems).to.eql(1);
     expect(user._tmp.quest.collection).to.eql(1);
@@ -50,9 +47,8 @@ describe('common.fns.randomDrop', () => {
     it('drops something when the task is a todo', () => {
       expect(user._tmp).to.eql({});
       user.flags.dropsEnabled = true;
-      predictableRandom = () => {
-        return 0.1;
-      };
+      predictableRandom.returns(0.1);
+
       randomDrop(user, { task, predictableRandom });
       expect(user._tmp).to.not.eql({});
     });
@@ -61,9 +57,8 @@ describe('common.fns.randomDrop', () => {
       task = generateHabit({ userId: user._id });
       expect(user._tmp).to.eql({});
       user.flags.dropsEnabled = true;
-      predictableRandom = () => {
-        return 0.1;
-      };
+      predictableRandom.returns(0.1);
+
       randomDrop(user, { task, predictableRandom });
       expect(user._tmp).to.not.eql({});
     });
@@ -72,9 +67,8 @@ describe('common.fns.randomDrop', () => {
       task = generateDaily({ userId: user._id });
       expect(user._tmp).to.eql({});
       user.flags.dropsEnabled = true;
-      predictableRandom = () => {
-        return 0.1;
-      };
+      predictableRandom.returns(0.1);
+
       randomDrop(user, { task, predictableRandom });
       expect(user._tmp).to.not.eql({});
     });
@@ -83,34 +77,30 @@ describe('common.fns.randomDrop', () => {
       task = generateReward({ userId: user._id });
       expect(user._tmp).to.eql({});
       user.flags.dropsEnabled = true;
-      predictableRandom = () => {
-        return 0.1;
-      };
+      predictableRandom.returns(0.1);
+
       randomDrop(user, { task, predictableRandom });
       expect(user._tmp).to.not.eql({});
     });
 
     it('drops food', () => {
-      predictableRandom = () => {
-        return 0.65;
-      };
+      predictableRandom.returns(0.65);
+
       randomDrop(user, { task, predictableRandom });
       expect(user._tmp.drop.type).to.eql('Food');
     });
 
     it('drops eggs', () => {
-      predictableRandom = () => {
-        return 0.35;
-      };
+      predictableRandom.returns(0.35);
+
       randomDrop(user, { task, predictableRandom });
       expect(user._tmp.drop.type).to.eql('Egg');
     });
 
     context('drops hatching potion', () => {
       it('drops a very rare potion', () => {
-        predictableRandom = () => {
-          return 0.01;
-        };
+        predictableRandom.returns(0.01);
+
         randomDrop(user, { task, predictableRandom });
         expect(user._tmp.drop.type).to.eql('HatchingPotion');
         expect(user._tmp.drop.value).to.eql(5);
@@ -118,9 +108,8 @@ describe('common.fns.randomDrop', () => {
       });
 
       it('drops a rare potion', () => {
-        predictableRandom = () => {
-          return 0.08;
-        };
+        predictableRandom.returns(0.08);
+
         randomDrop(user, { task, predictableRandom });
         expect(user._tmp.drop.type).to.eql('HatchingPotion');
         expect(user._tmp.drop.value).to.eql(4);
@@ -129,9 +118,8 @@ describe('common.fns.randomDrop', () => {
       });
 
       it('drops an uncommon potion', () => {
-        predictableRandom = () => {
-          return 0.17;
-        };
+        predictableRandom.returns(0.17);
+
         randomDrop(user, { task, predictableRandom });
         expect(user._tmp.drop.type).to.eql('HatchingPotion');
         expect(user._tmp.drop.value).to.eql(3);
@@ -140,9 +128,8 @@ describe('common.fns.randomDrop', () => {
       });
 
       it('drops a common potion', () => {
-        predictableRandom = () => {
-          return 0.20;
-        };
+        predictableRandom.returns(0.20);
+
         randomDrop(user, { task, predictableRandom });
         expect(user._tmp.drop.type).to.eql('HatchingPotion');
         expect(user._tmp.drop.value).to.eql(2);

website/common/script/fns/randomDrop.js

@@ -5,6 +5,9 @@ import { daysSince } from '../cron';
 import { diminishingReturns } from '../statHelpers';
 import randomVal from './randomVal';
 
+// TODO This is only used on the server
+// move to user model as an instance method?
+
 // Clone a drop object maintaining its functions so that we can change it without affecting the original item
 function cloneDropItem (drop) {
   return _.cloneDeep(drop, (val) => {
@@ -12,18 +15,20 @@ function cloneDropItem (drop) {
   });
 }
 
+function trueRandom () {
+  return Math.random();
+}
+
 module.exports = function randomDrop (user, options, req = {}) {
   let acceptableDrops;
-  let chance;
   let drop;
   let dropMultiplier;
   let rarity;
-  let task;
 
-  let predictableRandom = options.predictableRandom || Math.random;
-  task = options.task;
+  let predictableRandom = options.predictableRandom || trueRandom;
+  let task = options.task;
 
-  chance = _.min([Math.abs(task.value - 21.27), 37.5]) / 150 + 0.02;
+  let chance = _.min([Math.abs(task.value - 21.27), 37.5]) / 150 + 0.02;
   chance *= task.priority *                             // Task priority: +50% for Medium, +100% for Hard
     (1 + (task.streak / 100 || 0)) *                    // Streak bonus: +1% per streak
     (1 + user._statsComputed.per / 100) *               // PERception: +1% per point
@@ -35,7 +40,7 @@ module.exports = function randomDrop (user, options, req = {}) {
     }, 0) || 0));
   chance = diminishingReturns(chance, 0.75);
 
-  if (predictableRandom(user, user.stats.gp) < chance) {
+  if (predictableRandom() < chance) {
     if (!user.party.quest.progress.collectedItems) user.party.quest.progress.collectedItems = 0;
     user.party.quest.progress.collectedItems++;
     if (!user._tmp.quest) user._tmp.quest = {};
@@ -54,8 +59,8 @@ module.exports = function randomDrop (user, options, req = {}) {
     return;
   }
 
-  if (user.flags && user.flags.dropsEnabled && predictableRandom(user, user.stats.exp) < chance) {
-    rarity = predictableRandom(user, user.stats.gp);
+  if (user.flags && user.flags.dropsEnabled && predictableRandom() < chance) {
+    rarity = predictableRandom();
 
     if (rarity > 0.6) { // food 40% chance
       drop = cloneDropItem(randomVal(_.where(content.food, {