categorical 2dMap: fill missing category in input data with undefined

Author: antoinerg

src/traces/heatmap/clean_2d_array.js

@@ -31,6 +31,11 @@ module.exports = function clean2dArray(zOld, trace, xa, ya) {
         old2new = function(zOld, i, j) { return zOld[i][j]; };
     }
 
+    var padOld2new = function(zOld, i, j) {
+        if(i === undefined || j === undefined) return undefined;
+        return old2new(zOld, i, j);
+    };
+
     function axisMapping(ax) {
         if(trace && trace.type !== 'carpet' && trace.type !== 'contourcarpet' &&
             ax && ax.type === 'category' && trace['_' + ax._id.charAt(0)].length) {
@@ -51,10 +56,13 @@ module.exports = function clean2dArray(zOld, trace, xa, ya) {
 
     if(ya && ya.type === 'category') rowlen = ya._categories.length;
     for(i = 0; i < rowlen; i++) {
-        collen = getCollen(zOld, i);
-        if(xa && xa.type === 'category') collen = xa._categories.length;
+        if(xa && xa.type === 'category') {
+            collen = xa._categories.length;
+        } else {
+            collen = getCollen(zOld, i);
+        }
         zNew[i] = new Array(collen);
-        for(j = 0; j < collen; j++) zNew[i][j] = cleanZvalue(old2new(zOld, yMap(i), xMap(j)));
+        for(j = 0; j < collen; j++) zNew[i][j] = cleanZvalue(padOld2new(zOld, yMap(i), xMap(j)));
     }
 
     return zNew;