feature: updated downloadFile function and unit tests to cover new functionality

packages/common/src/download-file.function.spec.ts

@@ -1,23 +1,72 @@
-import { blobMock, jsonMock, nameMock } from '@bimeister/utilities.internal';
 import { downloadFile } from './download-file.function';
 
 describe('download-file.function.ts', () => {
-  const fileNameSample: string = nameMock;
+  const originalCreateObjectURL: (obj: Blob | MediaSource) => string = URL.createObjectURL;
+  const originalRevokeObjectURL: (url: string) => void = URL.revokeObjectURL;
+  let anchorClickSpy: jest.SpyInstance;
 
-  document.body.innerHTML = ``;
-  window.URL.createObjectURL = (): string => nameMock;
+  beforeEach(() => {
+    URL.createObjectURL = jest.fn(() => 'blob:http://localhost/sample');
+    URL.revokeObjectURL = jest.fn();
 
-  it('should create new DOM-element if data is Blob', () => {
-    const fileSample: Blob = blobMock;
-    downloadFile(fileNameSample, fileSample);
-    const aElement: HTMLAnchorElement | null = document.querySelector('a');
-    expect(aElement).toBeDefined();
+    anchorClickSpy = jest.spyOn(HTMLAnchorElement.prototype, 'click').mockImplementation();
+
+    document.body.innerHTML = '';
+  });
+
+  afterEach(() => {
+    URL.createObjectURL = originalCreateObjectURL;
+    URL.revokeObjectURL = originalRevokeObjectURL;
+    anchorClickSpy.mockRestore();
   });
 
-  it('should create new DOM-element if data is string', () => {
-    const fileSample: string = jsonMock;
-    downloadFile(fileNameSample, fileSample);
-    const aElement: HTMLAnchorElement | null = document.querySelector('a');
-    expect(aElement).toBeDefined();
+  it('should create an anchor element and trigger download using a presigned URL', () => {
+    const presignedUrl: string = 'https://example.com/path/to/file';
+
+    downloadFile(presignedUrl);
+
+    const anchor: HTMLAnchorElement | null = document.querySelector('a');
+    expect(anchor).toBeNull();
+    expect(anchorClickSpy).toHaveBeenCalledTimes(1);
+  });
+
+  it('should create an anchor element and download a file from a Blob', () => {
+    const filename: string = 'example.txt';
+    const blobData: Blob = new Blob(['Hello, world!'], { type: 'text/plain' });
+
+    downloadFile(filename, blobData);
+
+    const anchor: HTMLAnchorElement | null = document.querySelector('a');
+    expect(anchor).toBeNull();
+    expect(URL.createObjectURL).toHaveBeenCalledWith(blobData);
+    expect(URL.revokeObjectURL).toHaveBeenCalledWith('blob:http://localhost/sample');
+    expect(anchorClickSpy).toHaveBeenCalledTimes(1);
+  });
+
+  it('should create an anchor element and download a file from a string', () => {
+    const filename: string = 'example.txt';
+    const stringData: string = 'Sample data content';
+
+    downloadFile(filename, stringData);
+
+    const anchor: HTMLAnchorElement | null = document.querySelector('a');
+    expect(anchor).toBeNull();
+    expect(URL.createObjectURL).toHaveBeenCalledTimes(1);
+    expect(URL.revokeObjectURL).toHaveBeenCalledWith('blob:http://localhost/sample');
+    expect(anchorClickSpy).toHaveBeenCalledTimes(1);
+  });
+
+  it('should create an anchor element and download a file from a BlobPart (typed array)', () => {
+    const filename: string = 'example.bin';
+    const typedArray: Uint8Array = new Uint8Array([72, 101, 108, 108, 111]); // "Hello" in ASCII
+
+    downloadFile(filename, typedArray);
+
+    const anchor: HTMLAnchorElement | null = document.querySelector('a');
+    expect(anchor).toBeNull();
+    const expectedBlob: Blob = new Blob([typedArray]);
+    expect(URL.createObjectURL).toHaveBeenCalledWith(expectedBlob);
+    expect(URL.revokeObjectURL).toHaveBeenCalledWith('blob:http://localhost/sample');
+    expect(anchorClickSpy).toHaveBeenCalledTimes(1);
   });
 });

packages/common/src/download-file.function.ts

@@ -1,8 +1,49 @@
-export function downloadFile(filename: string, data: Blob | string): void {
-  const dataBlob: Blob = data instanceof Blob ? data : new Blob([data]);
+/* eslint-disable @typescript-eslint/unified-signatures */
+import { isNil } from './is-nil.function';
+
+/**
+ * Initiates a file download using a pre-signed URL.
+ *
+ * @param presignedUrl - The pre-signed URL from which the file will be downloaded.
+ *
+ * @example
+ * Download a file from a pre-signed URL:
+ * downloadFile('https://example.com/path/to/file');
+ */
+export function downloadFile(presignedUrl: string): void;
+
+/**
+ * Creates and downloads a file from the provided data.
+ *
+ * @param filename - The name under which the file will be saved.
+ * @param data - The data to be downloaded, provided as BlobPart.
+ *
+ * @example
+ * Download a file from Blob data:
+ * const data = new Blob(['Hello, world!'], { type: 'text/plain' });
+ * downloadFile('example.txt', data);
+ *
+ * @example
+ * Download a file from string data:
+ * const dataString = "Sample data content";
+ * downloadFile('example.txt', dataString);
+ */
+export function downloadFile(filename: string, data: BlobPart): void;
 
+export function downloadFile(filenameOrPresignedUrl: string, data?: BlobPart): void {
+  if (isNil(data)) {
+    const anchor: HTMLAnchorElement = document.createElement('a');
+    anchor.href = filenameOrPresignedUrl;
+    anchor.click();
+    anchor.remove();
+    return;
+  }
+
+  const dataBlob: Blob = data instanceof Blob ? data : new Blob([data]);
   const anchor: HTMLAnchorElement = document.createElement('a');
   anchor.href = URL.createObjectURL(dataBlob);
-  anchor.download = filename;
+  anchor.download = filenameOrPresignedUrl;
   anchor.click();
+  URL.revokeObjectURL(anchor.href);
+  anchor.remove();
 }