Two more optimizations: remove default value for predicate, and, use local variable...

[dygraphs.git] / dygraph-utils.js

diff --git a/dygraph-utils.js b/dygraph-utils.js
index c6c3a60..907069f 100644 (file)
--- a/dygraph-utils.js
+++ b/dygraph-utils.js
@@ -147,6 +147,21 @@ Dygraph.addEvent = function addEvent(elem, type, fn) {
 
 /**
  * @private
+ * Add an event handler. This event handler is kept until the graph is
+ * destroyed with a call to graph.destroy().
+ *
+ * @param { DOM element } elem The element to add the event to.
+ * @param { String } type The type of the event, e.g. 'click' or 'mousemove'.
+ * @param { Function } fn The function to call on the event. The function takes
+ * one parameter: the event object.
+ */
+Dygraph.prototype.addEvent = function addEvent(elem, type, fn) {
+  Dygraph.addEvent(elem, type, fn);
+  this.registeredEvents_.push({ elem : elem, type : type, fn : fn });
+};
+
+/**
+ * @private
  * Remove an event handler. This smooths a difference between IE and the rest of
  * the world.
  * @param { DOM element } elem The element to add the event to.
@@ -583,7 +598,7 @@ Dygraph.updateDeep = function (self, o) {
           // DOM objects are shallowly-copied.
           self[k] = o[k];
         } else if (typeof(o[k]) == 'object') {
-          if (typeof(self[k]) != 'object') {
+          if (typeof(self[k]) != 'object' || self[k] === null) {
             self[k] = {};
           }
           Dygraph.updateDeep(self[k], o[k]);
@@ -668,6 +683,66 @@ Dygraph.isAndroid = function() {
 
 /**
  * @private
+ * Returns a new iterator over array, between indexes start and 
+ * start + length, and only returns entries that pass the accept function
+ *
+ * @param array the array to iterate over.
+ * @param start the first index to iterate over
+ * @param length the number of elements in the array to iterate over.
+ * This, along with start, defines a slice of the array, and so length
+ * doesn't imply the number of elements in the iterator when accept
+ * doesn't always accept all values.
+ * @param predicate a function that takes parameters array and idx, which
+ * returns true when the element should be returned. If omitted, all
+ * elements are accepted.
+ *
+ * TODO(konigsberg): add default vlues to start and length.
+ */
+Dygraph.createIterator = function(array, start, length, predicate) {
+  var iter = new function() {
+    this.end_ = Math.min(array.length, start + length);
+    this.nextIdx_ = start - 1; // use -1 so initial call to advance works.
+    this.hasNext_ = true;
+    this.peek_ = null;
+    var self = this;
+
+    this.hasNext = function() {
+      return self.hasNext_;
+    }
+
+    this.next = function() {
+      if (self.hasNext_) {
+        var obj = self.peek_;
+        self.advance_();
+        return obj;
+      }
+      return null;
+    }
+    this.peek = function() {
+      return self.peek_;
+    }
+    this.advance_ = function() {
+      var nextIdx = self.nextIdx_;
+      nextIdx++;
+      while(nextIdx < self.end_) {
+        if (!predicate || predicate(array, nextIdx)) {
+          self.peek_ = array[nextIdx];
+          self.nextIdx_ = nextIdx;
+          return;
+        }
+        nextIdx++;
+      }
+      self.nextIdx_ = nextIdx;
+      self.hasNext_ = false;
+      self.peek_ = null;
+    }
+  };
+  iter.advance_();
+  return iter;
+};
+
+/**
+ * @private
  * Call a function N times at a given interval, then call a cleanup function
  * once. repeat_fn is called once immediately, then (times - 1) times
  * asynchronously. If times=1, then cleanup_fn() is also called synchronously.