# HG changeset patch
# User Jordi Gutiérrez Hermoso <jordi@ecometrica.com>
# Date 1535331393 14400
# Node ID b5a50b62ef91e3710cce617f609166d1e38d983d
# Parent  ddbcac0232d1b3a5e678e1c53336819cf363aead
xspline_at_t: fix check for null k4

diff --git a/splines.js b/splines.js
--- a/splines.js
+++ b/splines.js
@@ -276,12 +276,12 @@
     var k1_idx = (n + k1) % n,
         k2_idx = (n + k2) % n,
         k3_idx = (n + k3) % n,
-        k4_idx = k4 ? (n + k4) % n : null;
+        k4_idx = k4 != null ? (n + k4) % n : null;
 
     var f1t = fk(k1, t),
         f2t = fk(k2, t),
         f3t = fk(k3, t),
-        f4t = k4 ? fk(k4, t) : 0;
+        f4t = k4 != null ? fk(k4, t) : 0;
 
     // normalisation factor
     var denom = f1t + f2t + f3t + f4t;
@@ -289,7 +289,7 @@
     var p1 = nodes[k1_idx],
         p2 = nodes[k2_idx],
         p3 = nodes[k3_idx],
-        p4 = k4 ? nodes[k4_idx] : [0, 0];
+        p4 = k4 != null ? nodes[k4_idx] : [0, 0];
 
     var at_t = (f1t*p1[XorY] + f2t*p2[XorY] + f3t*p3[XorY] + f4t*p4[XorY])/denom;