seeded random

index.html

@@ -10,6 +10,8 @@
 
     <script src="js/csv.js"></script>
 
+    <script src="js/helpers/rand.js"></script>
+
     <script src="js/model/store.js"></script>
         <script src="js/model/data.js"></script>
 

public/js/controller/quizGenerator.js

 const lapk = (text)=>`„${text}“`;
 const rand = function(a, b){
     if(Array.isArray(a)){
-      return a[Math.random()*a.length|0];
+      return a[Math.random.seeded()*a.length|0];
     }
     if(typeof a === 'object' && 'max' in a){
       b = a.max;
@@ -9,7 +9,7 @@ const rand = function(a, b){
     }
     a = Math.ceil(a);
     b = Math.floor(b);
-    return Math.floor(Math.random() * (b - a + 1)) + a;
+    return Math.floor(Math.random.seeded() * (b - a + 1)) + a;
 
     return (r-a)*(b-a)|0;
   },
@@ -19,7 +19,7 @@ const rand = function(a, b){
       const item = items[ i ];
       sum += item.probability |0;
     }
-    const theRandom = Math.random();
+    const theRandom = Math.random.seeded();
     let total = 0;
 
     for( let i = 0, _i = items.length; i < _i; i++ ){
@@ -46,7 +46,7 @@ const quizTypes = {
 };
 const shuffle = function (a) {
   for (let i = a.length - 1; i > 0; i--) {
-    const j = Math.floor(Math.random() * (i + 1));
+    const j = Math.floor(Math.random.seeded() * (i + 1));
     [a[i], a[j]] = [a[j], a[i]];
   }
   return a;

public/js/helpers/rand.js

+function mulberry32(a) {
+  var out = function() {
+    var t = a += 0x6D2B79F5;
+    t = Math.imul(t ^ t >>> 15, t | 1);
+    t ^= t + Math.imul(t ^ t >>> 7, t | 61);
+    return ((t ^ t >>> 14) >>> 0) / 4294967296;
+  }
+
+  out.getSeed = function() {
+    return a;
+  };
+  out.setSeed = function(A) {
+    a = A;
+  };
+  out.setStringSeed = function(str) {
+    str = str.replace(/[^0-9a-z]/g,'');
+    if(str.length === 0)str = '1';
+    a = parseInt(str,36);
+  };
+  out.getStringSeed = function() {
+    return a.toString(36);
+  };
+  return out;
+}
+
+Math.random.seeded = mulberry32(Math.floor(Math.random()*4294967296));
\ No newline at end of file

public/js/view/page/generate.js

@@ -14,6 +14,8 @@ view.page.Generate = function() {
       type = store.get('generateType');
 
       try{
+        seedInput.value = Math.random.seeded.getStringSeed();
+
         const result = quizGenerator( type, photo );
 
         title.innerHTML = textFormat( result.question, true );
@@ -26,7 +28,8 @@ view.page.Generate = function() {
       }
   };
 
-  let title, answers, debug;
+  let title, answers, debug, seedInput, setSeed;
+
   this.dom =
     div({cls: 'generate-panel'},
       div({cls: 'title-gradient'},
@@ -45,7 +48,17 @@ view.page.Generate = function() {
       div({cls: 'generate-controls'},
         D.input({
           attr: {type: 'button', value: 'F5'},
-          on: {click: update}})),
+          on: {click: update}}),
+
+        span({cls: 'generate-seed-label'}, 'Seed:'),
+        seedInput = D.input({
+          cls: 'seed',
+          attr: {type: 'input', value: '', placeholder: 'seed'},
+          on: {change: function() {
+              Math.random.seeded.setStringSeed(seedInput.value);
+          }}}),
+
+      ),
 
       div({cls: 'generate-example'},
         title = div({cls: 'generate-title'}),

public/main.css

@@ -225,4 +225,7 @@ textarea.generate-debug {
 }
 .generate-controls {
     margin:16px
+}
+.generate-seed-label {
+    margin: 0 8px 0 32px
 }
\ No newline at end of file