Amend generateInternalStream typings to remove any

Fixes #423 #697

Author: Stuk

documentation/api_jszip/generate_internal_stream.md

@@ -21,13 +21,10 @@ __Metadata__ : see [the metadata of `generateAsync()`]({{site.baseurl}}/document
 ## Examples
 
 ```js
-zip.generateInternalStream({type:"blob"}).accumulate(function callback(err, content) {
-  if (err) {
-    // handle error
-  }
-  // see FileSaver.js
-  saveAs(content, "hello.zip");
-}, function updateCallback(metadata) {
-  // print progression with metadata.percent and metadata.currentFile
+zip
+.generateInternalStream({type:"uint8array"})
+.accumulate()
+.then(function (data) {
+    // data contains here the complete zip file as a uint8array (the type asked in generateInternalStream)
 });
 ```

index.d.ts

@@ -169,44 +169,45 @@ declare namespace JSZip {
         createFolders?: boolean;
         decodeFileName?: (bytes: string[] | Uint8Array | Buffer) => string;
     }
-}
 
-declare namespace StreamHelper {
-    type DataEventCallback = (dataChunk: any, metadata: any) => any
-    type EndEventCallback = () => any
-    type ErrorEventCallback = (error: Error) => any
+    interface JSZipMetadata {
+        percent: number;
+        currentFile: string;
+    }
+
+    type DataEventCallback<T> = (dataChunk: T, metadata: JSZipMetadata) => void
+    type EndEventCallback = () => void
+    type ErrorEventCallback = (error: Error) => void
 
-    interface StreamHelper {
+    interface JSZipStreamHelper<T> {
         /**
          * Register a listener on an event
-         *
-         * @param event The name of the event. Only 3 events are supported : data, end and error
-         * @param callback The function called when the event occurs
-         * @return The current StreamHelper object, for chaining
          */
-        on(event: 'data' | 'end' | 'error', callback: DataEventCallback | EndEventCallback | ErrorEventCallback);
+        on(event: 'data', callback: DataEventCallback<T>): this;
+        on(event: 'end', callback: EndEventCallback): this;
+        on(event: 'error', callback: ErrorEventCallback): this;
 
         /**
          * Read the whole stream and call a callback with the complete content
          *
          * @param updateCallback The function called every time the stream updates
          * @return A Promise of the full content
          */
-        accumulate(updateCallback?: (metadata: any) => any): Promise<any>;
+        accumulate(updateCallback?: (metadata: JSZipMetadata) => void): Promise<T>;
 
         /**
          * Resume the stream if the stream is paused. Once resumed, the stream starts sending data events again
          *
          * @return The current StreamHelper object, for chaining
          */
-        resume(): StreamHelper;
+        resume(): this;
 
         /**
          * Pause the stream if the stream is running. Once paused, the stream stops sending data events
          *
          * @return The current StreamHelper object, for chaining
          */
-        pause(): StreamHelper;
+        pause(): this;
     }
 }
 
@@ -303,7 +304,7 @@ interface JSZip {
      * @param options Optional options for the generator
      * @return a StreamHelper
      */
-    generateInternalStream(options?: JSZip.JSZipGeneratorOptions): StreamHelper.StreamHelper
+    generateInternalStream<T extends JSZip.OutputType>(options?: JSZip.JSZipGeneratorOptions<T>): JSZip.JSZipStreamHelper<OutputByType[T]>;
 
     /**
      * Deserialize zip file asynchronously