added possibility to add file programmatically to the upload

core/projects/just-upload/README.md

@@ -19,7 +19,7 @@ provide `services` , `models` and `examples` to implement your own custom upload
   - `Basic Upload Multipart` - uploads files as `multipart/form-data`
     - [see Basic Multipart Example](https://github.com/andreashauschild/just-upload/blob/main/core/projects/example-app/src/app/examples/basic-multipart-example/basic-multipart-example.component.ts)
     - [Quarkus Endpoint (BasicUploadResource.java)](https://github.com/andreashauschild/just-upload/blob/main/dev/servers/quarkus/src/main/java/de/litexo/BasicUploadResource.java)
-  - `Chunked Upload` - Splits a file in chunks and sends for each chunk a http request. This can be used to upload very large files which may exceeding the size of a single
+  - `Chunked Upload` - Splits a file in chunks and sends for each chunk a http request. This can be used to upload very large files which may exceeding the size limit of a single
     request. 
     - [see Basic Chunked Upload Example](https://github.com/andreashauschild/just-upload/blob/main/core/projects/example-app/src/app/examples/basic-chunked-upload-example/basic-chunked-upload-example.component.ts)
     - [Quarkus Endpoint (ChunkUploadResource.java)](https://github.com/andreashauschild/just-upload/blob/main/dev/servers/quarkus/src/main/java/de/litexo/ChunkUploadResource.java)
@@ -169,11 +169,13 @@ The `UploadFile` is the file data model. It holds the browser file and additiona
 The `Upload` and `MultipartFormUpload` will be created by a factory method of the `JustUploadService`. It is the main object you will work with. In case of `MultipartFormUpload` every file will be sent as single `multipart/form-data` request. This means if you have 5 files in your file list, they will be sent in 5 separate requests. 
 If you use `Upload` every file will be sent as an `application/octet-stream` to the server.
 
-| Methods   |      Description      |
-|----------|---------------|
-| `uploadFile(uploadFile: UploadFile): void` | Method to trigger the upload process of the given file. The method can be used if `uploadImmediately` is disabled  |
-| `onFileProcessed(): Observable<UploadFile>` | Subscribe for receiving progress chances while the file is processed. Returns`UploadFile` with the current state. **Info:** If you are uploading files with a very good connection (e.g. local server) you may get only one processing update   |
-| `onFiledAdded(): Observable<UploadFile>` | Subscribe for receiving the files that are added to the `input` element  |
+| Methods   | Description                                                                                                                                                                                                                                   |
+|----------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `uploadFile(uploadFile: UploadFile): void` | Method to trigger the upload process of the given file. The method can be used if `uploadImmediately` is disabled                                                                                                                             |
+| `onFileProcessed(): Observable<UploadFile>` | Subscribe for receiving progress chances while the file is processed. Returns`UploadFile` with the current state. **Info:** If you are uploading files with a very good connection (e.g. local server) you may get only one processing update |
+| `onFiledAdded(): Observable<UploadFile>` | Subscribe for receiving the files that are added to the `input` element                                                                                                                                                                       |
+| `addFile(file: File): void` | Adds the File): to the upload. This can be used add files programmatically if needed. For example if you build drag and drop components.|
+| `addFiles(fileList: FileList): void` | Adds the FileList to the upload. This can be used add files programmatically if needed. For example if you build drag and drop components.|
 
 ## ChunkedUploadConfig - ChunkedUploadFile - ChunkedUpload
 Chunked Upload - Splits a file in chunks and sends for each chunk a http request. This can be used to upload very large files which may exceeding the size of a single
@@ -237,3 +239,5 @@ Every chunk will be sent as an `application/octet-stream` to the server.
 | `onChunkProcessed(): Observable<ChunkedUploadFile>` | Subscribe to this function to handle chunks after there where send to server  |
 | `onFiledAdded(): Observable<ChunkedUploadFile>` |  Subscribe for receiving the files that are added to the `input` element  |
 | `uploadFile(file: ChunkedUploadFile): void` | Method to trigger the upload process of the given file. The method can be used if `uploadImmediately` is disabled  |
+| `addFile(file: File): void` | Adds the File): to the upload. This can be used add files programmatically if needed. For example if you build drag and drop components.|
+| `addFiles(fileList: FileList): void` | Adds the FileList to the upload. This can be used add files programmatically if needed. For example if you build drag and drop components.|

core/projects/just-upload/src/lib/BasicUpload.ts

@@ -18,10 +18,10 @@ export abstract class BasicUpload {
   constructor(protected http: HttpClient, input: ElementRef, config: UploadConfig) {
 
     if (!config) {
-      throw `Error: Missing config for upload!`
+      throw new Error(`Error: Missing config for upload!`);
     }
     if (!input) {
-      throw `Error: Missing input element for upload!`
+      throw  new Error(`Error: Missing input element for upload!`);
     }
 
 
@@ -124,20 +124,41 @@ export abstract class BasicUpload {
     if (input) {
       this.input.nativeElement.accept = this.config.accept;
       this.input.nativeElement.multiple = this.config.multi;
-      input.onchange = (e => {
-        if (input?.files?.length) {
-          for (let index = 0; index < input?.files?.length; index++) {
-            const uploadFile = new UploadFile(input.files[index]);
-            if (uploadFile.size > this.config.maxFileSize!) {
-              uploadFile.state = UploadState.SIZE_LIMIT_EXCEEDED;
-            }
-            this.fileAddedSubject.next(uploadFile);
-            if (this.config.uploadImmediately) {
-              this.uploadFile(uploadFile);
-            }
-          }
+      input.onchange = (_ => {
+        if (input?.files) {
+          this.addFiles(input.files);
         }
       });
     }
   }
+
+  /**
+   * Adds a file to this upload
+   * @param file
+   */
+  public addFile(file: File | null | undefined): void {
+    if (file) {
+      const uploadFile = new UploadFile(file);
+      if (uploadFile.size > this.config.maxFileSize!) {
+        uploadFile.state = UploadState.SIZE_LIMIT_EXCEEDED;
+      }
+      this.fileAddedSubject.next(uploadFile);
+      if (this.config.uploadImmediately) {
+        this.uploadFile(uploadFile);
+      }
+    }
+  }
+
+  /**
+   * Adds a FileList to this upload
+   * @param fileList
+   */
+  public addFiles(fileList: FileList | null | undefined): void {
+
+    if (fileList) {
+      for (let index = 0; index < fileList.length; index++) {
+        this.addFile(fileList.item(index));
+      }
+    }
+  }
 }