merge2: Fix compile error, clean up types (DefinitelyTyped#19207)

Author: Andy

types/merge2/index.d.ts

@@ -6,36 +6,6 @@
 
 /// <reference types="node" />
 
-import { DuplexOptions } from 'stream';
-
-type StreamType = NodeJS.ReadableStream | Merge2Stream;
-
-interface Merge2Stream extends NodeJS.ReadWriteStream {
-    /**
-     * @summary    Add more streams to an existing merged stream
-     *
-     * @param      {...(StreamType|StreamType[])} args  streams to add
-     *
-     * @return     The merged stream
-     */
-    add(...args: Array<StreamType | StreamType[]>): Merge2Stream;
-
-    /**
-     * @summary    It will emit 'queueDrain' when all streams merged.
-     *             If you set end === false in options, this event give you a notice that
-     *             you should add more streams to merge, or end the mergedStream.
-     *
-     * @param      {string} event  The 'queueDrain' event
-     *
-     * @return     This stream
-     */
-    on(event: 'queueDrain', listener: () => void): this;
-    on(event: string, listener: (...args: any[]) => void): this;
-
-    once(event: 'queueDrain', listener: () => void): this;
-    once(event: string, listener: (...args: any[]) => void): this;
-}
-
 /**
  * @summary        This function takes an arbitrary number of streams and returns a
  *                 Merge2Stream.
@@ -45,13 +15,53 @@ interface Merge2Stream extends NodeJS.ReadWriteStream {
  *
  * @see            { @link https://github.com/teambition/merge2#api }
  *
- * @param          {...(StreamType|StreamType[])} args  StreamTypes
- * @param          {DuplexOptions} opts  Optional DuplexOption to be specified last
+ * @param          args  StreamTypes
+ * @param          opts  Optional DuplexOption to be specified last
  *
  * @return         A merged duplex stream
  */
-declare function IMerge2(...args: Array<StreamType | StreamType[] | DuplexOptions>): Merge2Stream;
+declare function merge2(a: Streams, options?: merge2.Options): merge2.Merge2Stream;
+declare function merge2(a: Streams, b: Streams, options?: merge2.Options): merge2.Merge2Stream;
+declare function merge2(a: Streams, b: Streams, c: Streams, options?: merge2.Options): merge2.Merge2Stream;
+declare function merge2(a: Streams, b: Streams, c: Streams, d: Streams, options?: merge2.Options): merge2.Merge2Stream;
+declare function merge2(a: Streams, b: Streams, c: Streams, d: Streams, e: Streams, options?: merge2.Options): merge2.Merge2Stream;
+declare function merge2(...args: Streams[]): merge2.Merge2Stream;
+
+type Streams = merge2.StreamType | merge2.StreamType[];
+
+declare namespace merge2 {
+    type StreamType = NodeJS.ReadableStream | Merge2Stream;
 
-declare namespace IMerge2 {}
+    interface Options {
+        end?: boolean;
+        objectMode?: boolean;
+    }
+
+    interface Merge2Stream extends NodeJS.ReadWriteStream {
+        /**
+         * @summary    Add more streams to an existing merged stream
+         *
+         * @param      args  streams to add
+         *
+         * @return     The merged stream
+         */
+        add(...args: Streams[]): Merge2Stream;
+
+        /**
+         * @summary    It will emit 'queueDrain' when all streams merged.
+         *             If you set end === false in options, this event give you a notice that
+         *             you should add more streams to merge, or end the mergedStream.
+         *
+         * @param      {string} event  The 'queueDrain' event
+         *
+         * @return     This stream
+         */
+        on(event: 'queueDrain', listener: () => void): this;
+        on(event: string, listener: (...args: any[]) => void): this;
+
+        once(event: 'queueDrain', listener: () => void): this;
+        once(event: string, listener: (...args: any[]) => void): this;
+    }
+}
 
-export = IMerge2;
+export = merge2;