isolating state logic in getFilterFn

Author: noway

src/traces/candlestick/transform.js

@@ -114,16 +114,10 @@ exports.calcTransform = function calcTransform(gd, trace, opts) {
         y.push(l, o, c, c, c, h);
     };
 
-    var isPrevThisDirection = null;
-
     for(var i = 0; i < len; i++) {
-        if(filterFn(open[i], close[i], isPrevThisDirection, open[i - 1], close[i - 1])) {
+        if(filterFn(open[i], close[i])) {
             appendX(i);
             appendY(open[i], high[i], low[i], close[i]);
-            isPrevThisDirection = true;
-        } else {
-            isPrevThisDirection = false;
-            // not adding this candle to this direction bunch
         }
     }
 

src/traces/ohlc/helpers.js

@@ -95,9 +95,15 @@ exports.makeTransform = function(traceIn, state, direction) {
 };
 
 exports.getFilterFn = function(direction) {
+
+    var fn;
+    var isPrevThisDirection = null;
+    var oprev = null;
+    var cprev = null;
+
     switch(direction) {
         case 'increasing':
-            return function(o, c, isPrevThisDirection, oprev, cprev) {
+            var fn = function(o, c) {
                 if(o === c) {
                     if(c > cprev) {
                         return true; // increasing
@@ -115,9 +121,10 @@ exports.getFilterFn = function(direction) {
                 }
                 return o < c;
             };
+            break;
 
         case 'decreasing':
-            return function(o, c, isPrevThisDirection, oprev, cprev) {
+            var fn = function(o, c) {
                 if(o === c) {
                     if(c > cprev) {
                         return false; // increasing
@@ -135,7 +142,17 @@ exports.getFilterFn = function(direction) {
                 }
                 return o > c;
             };
+            break
     }
+    
+    return function(o, c) {
+        var out = fn(o, c);
+        isPrevThisDirection = !!out;
+        oprev = o;
+        cprev = c;
+        return out;
+    };
+
 };
 exports.addRangeSlider = function(data, layout) {
     var hasOneVisibleTrace = false;

src/traces/ohlc/transform.js

@@ -194,16 +194,11 @@ exports.calcTransform = function calcTransform(gd, trace, opts) {
         textOut.push(_t, _t, _t, _t, _t, _t, null);
     };
 
-    var isPrevThisDirection = null;
     for(var i = 0; i < len; i++) {
-        if(filterFn(open[i], close[i], isPrevThisDirection, open[i - 1], close[i - 1])) {
+        if(filterFn(open[i], close[i])) {
             appendX(i);
             appendY(open[i], high[i], low[i], close[i]);
             appendText(i, open[i], high[i], low[i], close[i]);
-            isPrevThisDirection = true;
-        } else {
-            isPrevThisDirection = false;
-            // not adding this candle to this direction bunch
         }
     }