+Dygraph.Iterator = function(array, start, length, predicate) {
+ start = start || 0;
+ length = length || array.length;
+ this.hasNext = true; // Use to identify if there's another element.
+ this.peek = null; // Use for look-ahead
+ this.start_ = start;
+ this.array_ = array;
+ this.predicate_ = predicate;
+ this.end_ = Math.min(array.length, start + length);
+ this.nextIdx_ = start - 1; // use -1 so initial advance works.
+ this.next(); // ignoring result.
+}
+
+Dygraph.Iterator.prototype.next = function() {
+ if (!this.hasNext) {
+ return null;
+ }
+ var obj = this.peek;
+
+ var nextIdx = this.nextIdx_ + 1;
+ var found = false;
+ while (nextIdx < this.end_) {
+ if (!this.predicate_ || this.predicate_(this.array_, nextIdx)) {
+ this.peek = this.array_[nextIdx];
+ found = true;
+ break;
+ }
+ nextIdx++;
+ }
+ this.nextIdx_ = nextIdx;
+ if (!found) {
+ this.hasNext = false;
+ this.peek = null;
+ }
+ return obj;
+}
+