rewrite forEach and isLinked - add comment - etc

Author: archmoj

src/plots/cartesian/axes.js

@@ -56,14 +56,17 @@ axes.setConvert = require('./set_convert');
 var autoType = require('./axis_autotype');
 
 var axisIds = require('./axis_ids');
+var idSort = axisIds.idSort;
+var isLinked = axisIds.isLinked;
+
+// tight coupling to chart studio so should generally not be expanded.
 axes.id2name = axisIds.id2name;
 axes.name2id = axisIds.name2id;
 axes.cleanId = axisIds.cleanId;
 axes.list = axisIds.list;
 axes.listIds = axisIds.listIds;
 axes.getFromId = axisIds.getFromId;
 axes.getFromTrace = axisIds.getFromTrace;
-axes.isLinked = axisIds.isLinked;
 
 var autorange = require('./autorange');
 axes.getAutoRange = autorange.getAutoRange;
@@ -2908,7 +2911,7 @@ axes.drawZeroLine = function(gd, ax, opts) {
             // If several zerolines enter at the same time we will sort once per,
             // but generally this should be a minimal overhead.
             opts.layer.selectAll('path').sort(function(da, db) {
-                return axisIds.idSort(da.id, db.id);
+                return idSort(da.id, db.id);
             });
         });
 
@@ -3207,7 +3210,7 @@ axes.drawLabels = function(gd, ax, opts) {
     if(
         anchorAx && anchorAx.autorange &&
         (ax.ticklabelposition || '').indexOf('inside') !== -1 &&
-        !axisIds.isLinked(fullLayout, ax._id)
+        !isLinked(fullLayout, ax._id)
     ) {
         if(!fullLayout._insideTickLabelsAutorange) {
             fullLayout._insideTickLabelsAutorange = {};

src/plots/cartesian/axis_ids.js

@@ -137,25 +137,18 @@ exports.ref2id = function(ar) {
     return (/^[xyz]/.test(ar)) ? ar.split(' ')[0] : false;
 };
 
-
-exports.isLinked = function(fullLayout, axId) {
-    var linked = false;
-
-    (fullLayout._axisConstraintGroups || []).forEach(function(e) {
-        if(e[axId]) {
-            linked = true;
-            return;
+function isFound(axId, list) {
+    if(list && list.length) {
+        for(var i = 0; i < list.length; i++) {
+            if(list[i][axId]) return true;
         }
-    });
-
-    if(!linked) {
-        (fullLayout._axisMatchGroups || []).forEach(function(e) {
-            if(e[axId]) {
-                linked = true;
-                return;
-            }
-        });
     }
+    return false;
+}
 
-    return linked;
+exports.isLinked = function(fullLayout, axId) {
+    return (
+        isFound(axId, fullLayout._axisMatchGroups) ||
+        isFound(axId, fullLayout._axisConstraintGroups)
+    );
 };