fix bug: curve-fit generates NaN with straight line.

Author: zbryikt

dist/easing-fit.bundle.js

@@ -80,6 +80,12 @@ fit = function(func, opt){
         j = k$;
         ncurve.push([Math.round(((curve[j][0] - x1) / (x2 - x1)) / opt.precision) * opt.precision, Math.round(((curve[j][1] - y1) / (y2 - y1)) / opt.precision) * opt.precision]);
       }
+      if (isNaN(ncurve[1][1])) {
+        ncurve[1][1] = ncurve[1][0];
+      }
+      if (isNaN(ncurve[2][1])) {
+        ncurve[2][1] = ncurve[2][0];
+      }
       keyframes.push({
         percent: round(x1 * 100),
         value: y1,

dist/easing-fit.bundle.min.js

@@ -70,6 +70,10 @@ fit = (func, opt = {}) ->
           Math.round(((curve[j].0 - x1) / (x2 - x1)) / opt.precision) * opt.precision,
           Math.round(((curve[j].1 - y1) / (y2 - y1)) / opt.precision) * opt.precision
         ]
+      # if all y in ps are the same (flat line), then ncurve.*.1 will be NaN.
+      # simply make it the same with ncurve.*.0 to make a straight line bezier-curve.
+      if isNaN(ncurve.1.1) => ncurve.1.1 = ncurve.1.0
+      if isNaN(ncurve.2.1) => ncurve.2.1 = ncurve.2.0
       keyframes.push do
         percent: round(x1 * 100)
         value: y1