Adding helper functions to copy and download strings

src/utils/__tests__/copy_to_clipboard.test.tsx

@@ -0,0 +1,29 @@
+// Copyright (c) 2018 Ultimaker B.V.
+import copyToClipboard from '../copy_to_clipboard';
+
+test('Copy to clipboard', () => {
+    // prepare mock
+    const elementMock = {focus: jest.fn(), select: jest.fn(), style: {}};
+    const createElementSpy = jest.spyOn(document, 'createElement').mockReturnValue(elementMock);
+    const appendChildSpy = jest.spyOn(document.body, 'appendChild').mockImplementation();
+    const removeChildSpy = jest.spyOn(document.body, 'removeChild').mockImplementation();
+    const execCommandMock = jest.fn();
+    document.execCommand = execCommandMock;
+
+    // click copy button
+    copyToClipboard('the string that should be copied');
+
+    // copy must have been executed
+    expect(createElementSpy).toHaveBeenCalledWith('textarea');
+    expect(elementMock).toEqual({
+        style: {left: '0', opacity: '0', position: "fixed", top: '0'},
+        focus: expect.any(Function),
+        select: expect.any(Function),
+        value: "the string that should be copied",
+    });
+    expect(elementMock.focus).toHaveBeenCalledWith();
+    expect(elementMock.select).toHaveBeenCalledWith();
+    expect(appendChildSpy).toHaveBeenCalledWith(elementMock);
+    expect(removeChildSpy).toHaveBeenCalledWith(elementMock);
+    expect(execCommandMock).toHaveBeenCalledWith('copy');
+})

src/utils/__tests__/download_file.test.tsx

@@ -0,0 +1,24 @@
+// Copyright (c) 2018 Ultimaker B.V.
+
+import downloadFile from '../download_file';
+
+test('Downloading a file', () => {
+    // prepare mock
+    const elementMock = {click: jest.fn()};
+    const createElementSpy = jest.spyOn(document, 'createElement').mockReturnValue(elementMock);
+    const createObjectURL = jest.fn().mockReturnValue('obj://test-url');
+    global['URL']['createObjectURL'] = createObjectURL;
+
+    // click download button
+    downloadFile('file-name.txt', 'file contents');
+
+    // download must have been done
+    expect(createObjectURL).toHaveBeenCalledWith(expect.any(Blob));
+    expect(createElementSpy).toHaveBeenCalledWith('a');
+    expect(elementMock).toEqual({
+        click: expect.any(Function),
+        download: 'file-name.txt',
+        href: 'obj://test-url'
+    });
+    expect(elementMock.click).toHaveBeenCalledTimes(1);
+});

src/utils/copy_to_clipboard.tsx

@@ -0,0 +1,21 @@
+// Copyright (c) 2018 Ultimaker B.V.
+
+/**
+ * Copies a string to the user's clipboard.
+ * @param value - The string to be copied.
+ */
+export function copyToClipboard(value: string){
+    let selectionTextarea = document.createElement('textarea');
+    selectionTextarea.style.position = 'fixed';
+    selectionTextarea.style.left = '0';
+    selectionTextarea.style.top = '0';
+    selectionTextarea.style.opacity = '0';
+    selectionTextarea.value = value;
+    document.body.appendChild(selectionTextarea);
+    selectionTextarea.focus();
+    selectionTextarea.select();
+    document.execCommand('copy');
+    document.body.removeChild(selectionTextarea);
+}
+
+export default copyToClipboard;

src/utils/download_file.tsx

@@ -0,0 +1,17 @@
+// Copyright (c) 2018 Ultimaker B.V.
+
+/**
+ * Allows the user to download a file with the given contents.
+ * @param fileName - The default name of the file.
+ * @param fileContent - The content of the file.
+ * @param contentType - The content type, including the charset. Defaults to "text/plain;charset=utf-8".
+ */
+function downloadFile(fileName: string, fileContent: string, contentType?: string) {
+    const blob = new Blob([fileContent], { type: contentType || 'text/plain;charset=utf-8' });
+    const element = document.createElement('a');
+    element.href = URL.createObjectURL(blob);
+    element.download = fileName;
+    element.click();
+}
+
+export default downloadFile;