fix(typings): workaround typescript bugs when noImplicitAny or strict…

…NullChecks are not true

src/asynciterable/distinct.ts

@@ -20,7 +20,7 @@ export class DistinctAsyncIterable<TSource, TKey> extends AsyncIterableX<TSource
   }
 
   async *[Symbol.asyncIterator]() {
-    let set = [];
+    let set = [] as TKey[];
 
     for await (let item of <AsyncIterable<TSource>>this._source) {
       let key = await this._keySelector(item);

src/asynciterable/except.ts

@@ -19,7 +19,7 @@ export class ExceptAsyncIterable<TSource> extends AsyncIterableX<TSource> {
   }
 
   async *[Symbol.asyncIterator]() {
-    let map = [];
+    let map = [] as TSource[];
     for await (let secondItem of this._second) {
       map.push(secondItem);
     }

src/asynciterable/flatten.ts

@@ -16,7 +16,7 @@ export class FlattenAsyncIterable<TSource> extends AsyncIterableX<TSource> {
       for await (let item of source) {
         yield item;
       }
-      return;
+      return undefined;
     }
     for await (let item of source) {
       if (isAsyncIterable(item)) {

src/asynciterable/intersect.ts

@@ -32,7 +32,7 @@ export class IntersectAsyncIterable<TSource> extends AsyncIterableX<TSource> {
   }
 
   async *[Symbol.asyncIterator]() {
-    let map = [];
+    let map = [] as TSource[];
     for await (let secondItem of this._second) {
       map.push(secondItem);
     }

src/asynciterable/reverse.ts

@@ -9,7 +9,7 @@ export class ReverseAsyncIterable<TSource> extends AsyncIterableX<TSource> {
   }
 
   async *[Symbol.asyncIterator]() {
-    let results = [];
+    let results = [] as TSource[];
     for await (let item of this._source) {
       results.unshift(item);
     }

src/asynciterable/skiplast.ts

@@ -11,7 +11,7 @@ export class SkipLastAsyncIterable<TSource> extends AsyncIterableX<TSource> {
   }
 
   async *[Symbol.asyncIterator]() {
-    let q = [];
+    let q = [] as TSource[];
     for await (let item of this._source) {
       q.push(item);
       if (q.length > this._count) {

src/asynciterable/takelast.ts

@@ -11,20 +11,18 @@ export class TakeLastAsyncIterable<TSource> extends AsyncIterableX<TSource> {
   }
 
   async *[Symbol.asyncIterator]() {
-    if (this._count === 0) {
-      return;
-    }
-
-    let q = [];
-    for await (let item of this._source) {
-      if (q.length >= this._count) {
-        q.shift();
+    if (this._count > 0) {
+      let q = [] as TSource[];
+      for await (let item of this._source) {
+        if (q.length >= this._count) {
+          q.shift();
+        }
+        q.push(item);
       }
-      q.push(item);
-    }
 
-    while (q.length > 0) {
-      yield q.shift()!;
+      while (q.length > 0) {
+        yield q.shift()!;
+      }
     }
   }
 }

src/asynciterable/toarray.ts

@@ -1,5 +1,5 @@
 export async function toArray<TSource>(source: AsyncIterable<TSource>): Promise<TSource[]> {
-  let results = [];
+  let results = [] as TSource[];
   for await (let item of source) {
     results.push(item);
   }

src/asynciterable/union.ts

@@ -19,7 +19,7 @@ export class UnionAsyncIterable<TSource> extends AsyncIterableX<TSource> {
   }
 
   async *[Symbol.asyncIterator]() {
-    let map = [];
+    let map = [] as TSource[];
     for await (let lItem of this._left) {
       if ((await arrayIndexOfAsync(map, lItem, this._comparer)) === -1) {
         map.push(lItem);

src/asynciterable/zip.ts

@@ -15,7 +15,7 @@ export class ZipAsyncIterable<TSource, TResult> extends AsyncIterableX<TResult>
     this._fn = fn;
   }
 
-  async *[Symbol.asyncIterator]() {
+  async *[Symbol.asyncIterator](): AsyncIterableIterator<TResult> {
     const fn = this._fn;
     const sourcesLength = this._sources.length;
     const its = this._sources.map(x => x[Symbol.asyncIterator]());
@@ -25,7 +25,7 @@ export class ZipAsyncIterable<TSource, TResult> extends AsyncIterableX<TResult>
         const result = await its[i].next();
         if (result.done) {
           await Promise.all(its.map(returnAsyncIterator));
-          return;
+          return undefined;
         }
         values[i] = result.value;
       }

src/iterable/distinct.ts

@@ -20,7 +20,7 @@ export class DistinctIterable<TSource, TKey> extends IterableX<TSource> {
   }
 
   *[Symbol.iterator]() {
-    let set = [];
+    let set = [] as TKey[];
 
     for (let item of this._source) {
       let key = this._keySelector(item);

src/iterable/except.ts

@@ -19,7 +19,7 @@ export class ExceptIterable<TSource> extends IterableX<TSource> {
   }
 
   *[Symbol.iterator]() {
-    let map = [];
+    let map = [] as TSource[];
     for (let secondItem of this._second) {
       map.push(secondItem);
     }

src/iterable/flatten.ts

@@ -16,7 +16,7 @@ export class FlattenIterable<TSource> extends IterableX<TSource> {
       for (let item of source) {
         yield item;
       }
-      return;
+      return undefined;
     }
     for (let item of source) {
       if (isIterable(item)) {

src/iterable/intersect.ts

@@ -28,7 +28,7 @@ export class IntersectIterable<TSource> extends IterableX<TSource> {
   }
 
   *[Symbol.iterator]() {
-    let map = [];
+    let map = [] as TSource[];
     for (let secondItem of this._second) {
       map.push(secondItem);
     }

src/iterable/reverse.ts

@@ -9,7 +9,7 @@ export class ReverseIterable<TSource> extends IterableX<TSource> {
   }
 
   *[Symbol.iterator]() {
-    let results = [];
+    let results = [] as TSource[];
     for (let item of this._source) {
       results.unshift(item);
     }

src/iterable/skiplast.ts

@@ -11,7 +11,7 @@ export class SkipLastIterable<TSource> extends IterableX<TSource> {
   }
 
   *[Symbol.iterator]() {
-    let q = [];
+    let q = [] as TSource[];
     for (let item of this._source) {
       q.push(item);
       if (q.length > this._count) {

src/iterable/takelast.ts

@@ -11,20 +11,18 @@ export class TakeLastIterable<TSource> extends IterableX<TSource> {
   }
 
   *[Symbol.iterator]() {
-    if (this._count === 0) {
-      return;
-    }
-
-    let q = [];
-    for (let item of this._source) {
-      if (q.length >= this._count) {
-        q.shift();
+    if (this._count > 0) {
+      let q = [] as TSource[];
+      for (let item of this._source) {
+        if (q.length >= this._count) {
+          q.shift();
+        }
+        q.push(item);
       }
-      q.push(item);
-    }
 
-    while (q.length > 0) {
-      yield q.shift()!;
+      while (q.length > 0) {
+        yield q.shift()!;
+      }
     }
   }
 }

src/iterable/toarray.ts

@@ -1,5 +1,5 @@
 export function toArray<TSource>(source: Iterable<TSource>): TSource[] {
-  let results = [];
+  let results = [] as TSource[];
   for (let item of source) {
     results.push(item);
   }

src/iterable/union.ts

@@ -19,7 +19,7 @@ export class UnionIterable<TSource> extends IterableX<TSource> {
   }
 
   *[Symbol.iterator]() {
-    let map = [];
+    let map = [] as TSource[];
     for (let lItem of this._left) {
       if (arrayIndexOf(map, lItem, this._comparer) === -1) {
         map.push(lItem);

src/iterable/zip.ts

@@ -11,7 +11,7 @@ export class ZipIterable<TSource, TResult> extends IterableX<TResult> {
     this._sources = sources;
     this._fn = fn;
   }
-  *[Symbol.iterator]() {
+  *[Symbol.iterator](): IterableIterator<TResult> {
     const fn = this._fn;
     const sourcesLength = this._sources.length;
     const its = this._sources.map(x => x[Symbol.iterator]());
@@ -21,7 +21,7 @@ export class ZipIterable<TSource, TResult> extends IterableX<TResult> {
         const result = its[index].next();
         if (result.done) {
           its.forEach(returnIterator);
-          return;
+          return undefined;
         }
         values[index] = result.value;
       }