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alle new

node_modules/lop/lib/lazy-iterators.js

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+var fromArray = exports.fromArray = function(array) {
+    var index = 0;
+    var hasNext = function() {
+        return index < array.length;
+    };
+    return new LazyIterator({
+        hasNext: hasNext,
+        next: function() {
+            if (!hasNext()) {
+                throw new Error("No more elements");
+            } else {
+                return array[index++];
+            }
+        }
+    });
+};
+
+var LazyIterator = function(iterator) {
+    this._iterator = iterator;
+};
+
+LazyIterator.prototype.map = function(func) {
+    var iterator = this._iterator;
+    return new LazyIterator({
+        hasNext: function() {
+            return iterator.hasNext();
+        },
+        next: function() {
+            return func(iterator.next());
+        }
+    });
+};
+
+LazyIterator.prototype.filter = function(condition) {
+    var iterator = this._iterator;
+    
+    var moved = false;
+    var hasNext = false;
+    var next;
+    var moveIfNecessary = function() {
+        if (moved) {
+            return;
+        }
+        moved = true;
+        hasNext = false;
+        while (iterator.hasNext() && !hasNext) {
+            next = iterator.next();
+            hasNext = condition(next);
+        }
+    };
+    
+    return new LazyIterator({
+        hasNext: function() {
+            moveIfNecessary();
+            return hasNext;
+        },
+        next: function() {
+            moveIfNecessary();
+            var toReturn = next;
+            moved = false;
+            return toReturn;
+        }
+    });
+};
+
+LazyIterator.prototype.first = function() {
+    var iterator = this._iterator;
+    if (this._iterator.hasNext()) {
+        return iterator.next();
+    } else {
+        return null;
+    }
+};
+
+LazyIterator.prototype.toArray = function() {
+    var result = [];
+    while (this._iterator.hasNext()) {
+        result.push(this._iterator.next());
+    }
+    return result;
+};