Implementing OfType(...)

lib/iterators.ts

@@ -132,6 +132,40 @@ export class DefaultIfEmptyIteratror<T> extends IteratorBase<T> {
 }
 
 
+export class OfTypeIteratror<T> extends IteratorBase<T> {
+
+    constructor(target: Iterator<T>, protected obj: any) {
+        super(target);
+    }
+
+    public next(value?: any): IteratorResult<T> {
+        var result: any;
+        do {
+            result = this._iterator.next();
+        } while (!result.done && !(result.value instanceof this.obj));
+        return result;
+    }
+}
+
+
+export class OfValueTypeIteratror<T> extends OfTypeIteratror<T> {
+
+    constructor(target: Iterator<T>, obj: any, protected typeName: string) {
+        super(target, obj);
+    }
+
+    public next(value?: any): IteratorResult<T> {
+        var result: any;
+        do {
+            result = this._iterator.next();
+        } while (!result.done && 
+                  this.typeName !== typeof(result.value) && 
+                 !(result.value instanceof this.obj));
+        return result;
+    }
+}
+
+
 export class MethodIteratror<T> extends IteratorBase<T> {
 
     constructor(iterator: Iterator<T>, protected _method: Function = null, protected _index = 0) {

lib/linq.ts

@@ -128,6 +128,7 @@ class EnumerableImpl<T> implements Enumerable<T>, Iterable<T>, IEnumerable<T> {
         (this as any)['groupBy'] = this.GroupBy;
         (this as any)['groupJoin'] = this.GroupJoin;
         (this as any)['intersect'] = this.Intersect;
+        (this as any)['ofType'] = this.OfType;
         (this as any)['join'] = this.Join;
         (this as any)['orderBy'] = this.OrderBy;
         (this as any)['orderByDescend'] = this.OrderByDescending;
@@ -550,6 +551,37 @@ class EnumerableImpl<T> implements Enumerable<T>, Iterable<T>, IEnumerable<T> {
     }
 
 
+    public OfType(obj: any): Enumerable<T> {
+        let typeName: string;
+        switch (obj) {
+            case Number:
+                return new EnumerableImpl<T>(this,
+                    () => new Iterator.OfValueTypeIteratror(this[Symbol.iterator](), 
+                                                            obj,
+                                                            Constant.CONST_NUMBER));
+            case Boolean:
+                return new EnumerableImpl<T>(this,
+                   () => new Iterator.OfValueTypeIteratror(this[Symbol.iterator](), 
+                                                        obj,
+                                                        Constant.CONST_BOOLEAN));
+            case String:
+                return new EnumerableImpl<T>(this,
+                   () => new Iterator.OfValueTypeIteratror(this[Symbol.iterator](), 
+                                                        obj,
+                                                        Constant.CONST_STRING));
+            case Symbol:
+                return new EnumerableImpl<T>(this,
+                   () => new Iterator.OfValueTypeIteratror(this[Symbol.iterator](), 
+                                                        obj,
+                                                        Constant.CONST_SYMBOL));
+        }
+
+        return new EnumerableImpl<T>(this,
+                   () => new Iterator.OfTypeIteratror(this[Symbol.iterator](), 
+                                                    obj));
+    }
+
+
     public OrderBy<K>(keySelect: (x: T) => K = Constant.selfFn, equal: (a: K, b: K) => number = (a, b) => <any>a - <any>b): Enumerable<T> {
         return new OrderedLinq<T>(this,
             (array: Array<T>) => new Iterator.ArrayIterator(array, 0, (i: number) => i >= array.length),

lib/utilities.ts

@@ -76,6 +76,10 @@ export const nothingFound = "No element satisfies the condition in predicate";
 export const noElements = "The source sequence is empty.";
 export const tooMany = "More than one element satisfies the condition in predicate.";
 export const outOfRange = "Argument Out Of Range";
-
-
+export const CONST_FUNCTION     = "function";
+export const CONST_BOOLEAN      = "boolean";
+export const CONST_NUMBER       = "number";
+export const CONST_OBJECT       = "object";
+export const CONST_STRING       = "string";
+export const CONST_SYMBOL       = "symbol";