Extract all the maths

diff --git a/js/animation.js b/js/animation.js
index 074b1df3dd15ec556ac3f2081d7f3dfe1b6b1d67..f33198215d0e0e5947c03c5480d673b83e0d0433 100644 (file)
--- a/js/animation.js
+++ b/js/animation.js
@@ -1,21 +1,18 @@
 (function () {
 
-  var canvas = document.querySelector('canvas'),
-      r = Math.random,
-      pi = Math.PI,
-      cos = Math.cos,
-      sin = Math.sin,
-      ctx = canvas.getContext('2d'),
+  var K = document.querySelector('canvas'),
+      { random: r, PI, cos, sin, floor, atan2 } = Math,
+      ctx = K.getContext('2d'),
       fps = 24,
       lst = 0,
       spd = 1,
       siz = 5 + rnd(10),
-      clr = !!(r() > 0.5),
-      ccl = !!(r() > 0.5),
+      clr = r() > 0.5,
+      ccl = r() > 0.5,
       I = Array(rnd(10) + 6).fill(null).map(() => ({
         x: rnd(64),
         y: rnd(64),
-        a: r() * 2 * pi,
+        a: r() * 2 * PI,
         c: Array(3).fill(rnd(256))
       })),
       SHP = [sqr, crc, hrt, chs, lch],
@@ -24,7 +21,7 @@
       pos = POS[rnd(POS.length)];
 
   function rnd (x) {
-    return Math.floor(r() * x);
+    return floor(r() * x);
   }
 
   function sqr(i) {
@@ -37,7 +34,7 @@
 
     var p = pos(i);
     ctx.beginPath();
-    ctx.arc(p.x, p.y, siz / 2, 0, 2 * pi);
+    ctx.arc(p.x, p.y, siz / 2, 0, 2 * PI);
     ctx.fill();
   }
 
@@ -68,12 +65,12 @@
     ctx.fillRect(p.x, p.y, siz, siz);
 
     ctx.beginPath();
-    ctx.arc(p.x + siz / 2, p.y, siz / 2, 0, 2 * pi, false);
+    ctx.arc(p.x + siz / 2, p.y, siz / 2, 0, 2 * PI, false);
     ctx.fill();
     ctx.closePath();
 
     ctx.beginPath();
-    ctx.arc(p.x + siz, p.y + siz / 2, siz / 2, 0, 2 * pi, false);
+    ctx.arc(p.x + siz, p.y + siz / 2, siz / 2, 0, 2 * PI, false);
     ctx.fill();
     ctx.closePath();
   }
@@ -99,11 +96,11 @@
     i.y = i.y + spd * sin(i.a);
 
     if (i.x < 0 || i.x > 64) {
-      i.a = Math.atan2(sin(i.a), -cos(i.a))
+      i.a = atan2(sin(i.a), -cos(i.a))
     }
 
     if (i.y < 0 || i.y > 64) {
-      i.a = Math.atan2(-sin(i.a), cos(i.a))
+      i.a = atan2(-sin(i.a), cos(i.a))
     }
   }