Data in Quasar Apps

Quasar is a VueJS framework for building iOS and Android apps with the Cordova platform.

SheetJS is a JavaScript library for reading and writing data from spreadsheets.

This demo uses Quasar and SheetJS to process data and generate spreadsheets. We'll explore how to load SheetJS in an Quasar app and use Quasar and Cordova features to extract data from, and write data to, spreadsheets on the device.

The "Demo" creates an app that looks like the screenshots below:

iOS	Android

Tested Deployments

This demo was tested in the following environments:

Real Devices

OS	Device	Quasar	Date
Android 30	NVIDIA Shield	2.16.4	2024-06-09
iOS 15.1	iPad Pro	2.16.4	2024-06-09

Simulators

OS	Device	Quasar	Dev Platform	Date
Android 34	Pixel 3a	2.16.4	darwin-arm	2024-06-09
iOS 17.5	iPhone SE (3rd gen)	2.16.4	darwin-arm	2024-06-09
Android 35	Pixel 3a	2.16.9	win11-x64	2024-08-20

Integration Details

The SheetJS NodeJS Module can be imported from any component or script in the app.

This demo will use the Quasar ViteJS starter project with VueJS and Cordova. The starter places the backing Cordova project in the src-cordova folder.

The complete solution uses cordova-plugin-file for file operations. It can be installed from the Cordova folder:

cd src-cordova
cordova plugin add cordova-plugin-file
cd ..

Reading data

The QFile¹ component presents an API reminiscent of File Input elements:

<q-file label="Load File" filled label-color="orange" @input="updateFile"/>

When binding to the input element, the callback receives an Event object. Using standard DOM operations, the file data can be pulled into an ArrayBuffer and parsed using the SheetJS read method². read returns a workbook³ object that holds data and metadata for each worksheet.

This snippet reads a workbook, pulls the first worksheet, generates an array of objects using the SheetJS sheet_to_json⁴ method, and updates state:

import { read } from 'xlsx';

// assuming `todos` is a standard VueJS `ref`
async function updateFile(v) { try {
  // `v.target.files[0]` is the desired file object
  const files = (v.target as HTMLInputElement).files;
  if(!files || files.length == 0) return;

  // read first file
  const wb = read(await files[0].arrayBuffer());

  // get data of first worksheet as an array of objects
  const data = utils.sheet_to_json(wb.Sheets[wb.SheetNames[0]]);

  // update state
  todos.value = data.map(row => ({id: row.Index, content: row.Name}));

} catch(e) { console.log(e); } }

Writing data

Starting from an array of objects, the SheetJS json_to_sheet method⁵ generates a SheetJS worksheet object. The book_append_sheet and book_new helper functions⁶ create a SheetJS workbook object that can be exported:

import { utils } from 'xlsx';

// assuming `todos` is a VueJS ref whose value is an array of objects
const ws = utils.json_to_sheet(todos.value);
const wb = utils.book_new();
utils.book_append_sheet(wb, ws, "SheetJSQuasar");

The SheetJS write function⁷ with the option type: "buffer" will generate Uint8Array objects that can be converted to blobs and exported:

import { write } from 'xlsx';

// on iOS and android, `XLSX.write` with type "buffer" returns a `Uint8Array`
const u8: Uint8Array = write(wb, {bookType: "xlsx", type: "buffer"});

The cordova-plugin-file API writes the data to the filesystem. The code uses the File and Directory Entries API⁸:

// Request filesystem access for persistent storage
window.requestFileSystem(window.PERSISTENT, 0, function(fs) {
  // Request a handle to "SheetJSQuasar.xlsx", making a new file if necessary
  fs.root.getFile("SheetJSQuasar.xlsx", {create: true}, entry => {
    // Request a FileWriter for writing data
    entry.createWriter(writer => {
      // The FileWriter API needs an actual Blob
      const data = new Blob([u8], {type: "application/vnd.ms-excel"});
      // This callback is called if the write is successful
      writer.onwriteend = () => {
        // TODO: show a dialog
      };
      // writer.onerror will be invoked if there is an error in writing

      // write the data
      writer.write(data);
    });
  });
});

Demo

The demo draws from the ViteJS example. Familiarity with VueJS and TypeScript is assumed.

0. Ensure all of the dependencies are installed. Install the CLI globally:

npm i -g @quasar/cli cordova

(you may need to run sudo npm i -g if there are permission issues)

Installation Notes (click to show)

Quasar requires Java 17

1. Create a new app:

npm init quasar

When prompted:

• "What would you like to build?": App with Quasar CLI, let's go!
• "Project folder": SheetJSQuasar
• "Pick Quasar version": Quasar v2 (Vue 3 | latest and greatest)
• "Pick script type": Typescript
• "Pick Quasar App CLI variant": Quasar App CLI with Vite 2 (stable | v1)
• "Package name": (press Enter, it will use the default sheetjsquasar)
• "Project product name": SheetJSQuasar
• "Project description": SheetJS + Quasar
• "Author": (press Enter, it will use your Git config settings)
• "Pick a Vue component style": Composition API
• "Pick your CSS preprocessor": None
• "Check the features needed for your project": Deselect everything (scroll down to each selected item and press Space)
• "Install project dependencies": Yes, use npm

2. Install dependencies:

cd SheetJSQuasar
npm i
npm i --save https://cdn.sheetjs.com/xlsx-0.20.3/xlsx-0.20.3.tgz

3. Set up Cordova:

npx cordova telemetry off
npx quasar mode add cordova

When prompted, enter the app id org.sheetjs.quasar.

It will create a new src-cordova folder. Continue in that folder:

cd src-cordova
npx cordova platform add ios
npx cordova plugin add cordova-plugin-wkwebview-engine
npx cordova plugin add cordova-plugin-file

If there is an error Could not load API for iOS project, it needs to be reset:

npx cordova platform rm ios
npx cordova platform add ios
npx cordova plugin add cordova-plugin-file

Return to the project directory:

cd ..

4. Enable file sharing and make the documents folder visible in the iOS app. The following lines must be added to src-cordova/platforms/ios/SheetJSQuasar/SheetJSQuasar-Info.plist:

src-cordova/platforms/ios/SheetJSQuasar/SheetJSQuasar-Info.plist (add to file)

<plist version="1.0">
<dict>
  <key>UIFileSharingEnabled</key>
  <true/>
  <key>LSSupportsOpeningDocumentsInPlace</key>
  <true/>
  <key>CFBundleDevelopmentRegion</key>

(The root element of the document is plist and it contains one dict child)

5. Start the development server:

npx quasar dev -m ios

If prompted to select an external IP, press Enter.

If the app is blank or not refreshing, delete the app and close the simulator, then restart the development process.

6. Add the Dialog plugin to quasar.config.js:

quasar.config.js (add highlighted line)

    framework: {
      config: {},
// ...
      // Quasar plugins
      plugins: ['Dialog']
    },

7. In the template section of src/pages/IndexPage.vue, replace the example with a Table, Save button and Load file picker component:

src/pages/IndexPage.vue (change highlighted lines)

<template>
  <q-page class="row items-center justify-evenly">
    <q-table :rows="todos" />
    <q-btn-group>
      <q-file label="Load File" filled label-color="orange" @input="updateFile"/>
      <q-btn label="Save File" @click="saveFile" />
    </q-btn-group>
  </q-page>
</template>

This uses two functions that should be added to the component script:

src/pages/IndexPage.vue (add highlighted lines)

    const meta = ref<Meta>({
      totalCount: 1200
    });
    function saveFile() {
    }
    async function updateFile(v: Event) {
    }
    return { todos, meta, saveFile, updateFile };
  }
});

The app should now show two buttons at the bottom:

If the app is blank or not refreshing, delete the app and close the simulator, then restart the development process.

8. Wire up the updateFile function:

src/pages/IndexPage.vue (add highlighted lines)

import { defineComponent, ref } from 'vue';
import { read, write, utils } from 'xlsx';
import { useQuasar } from 'quasar';

export default defineComponent({
// ...
    const $q = useQuasar();
    function dialogerr(e: Error) { $q.dialog({title: "Error!", message: e.message || String(e)}); }
    function saveFile() {
    }
    async function updateFile(v: Event) {
      try {
        const files = (v.target as HTMLInputElement).files;
        if(!files || files.length == 0) return;

        const wb = read(await files[0].arrayBuffer());

        const data = utils.sheet_to_json<any>(wb.Sheets[wb.SheetNames[0]]);
        todos.value = data.map(row => ({id: row.Index, content: row.Name}));
      } catch(e) { dialogerr(e); }
    }

To test that reading works:

• Download https://docs.sheetjs.com/pres.numbers
• In the simulator, click the Home icon to return to the home screen
• Click on the "Files" icon
• Click and drag pres.numbers from a Finder window into the simulator.

• Make sure "On My iPhone" is highlighted and select "Save"
• Click the Home icon again then select the SheetJSQuasar app
• Click the "Load" button, then select "Choose File" and select pres:

Once selected, the screen should refresh with new contents.

9. Wire up the saveFile function:

src/pages/IndexPage.vue (add highlighted lines)

    function saveFile() {
      /* generate workbook from state */
      const ws = utils.json_to_sheet(todos.value);
      const wb = utils.book_new();
      utils.book_append_sheet(wb, ws, "SheetJSQuasar");
      const u8: Uint8Array = write(wb, {bookType: "xlsx", type: "buffer"});
      const dir: string = $q.cordova.file.documentsDirectory || $q.cordova.file.externalApplicationStorageDirectory;

      /* save to file */
      window.requestFileSystem(window.PERSISTENT, 0, function(fs) {
        try {
          fs.root.getFile("SheetJSQuasar.xlsx", {create: true}, entry => {
            const msg = `File stored at ${dir} ${entry.fullPath}`;
            entry.createWriter(writer => {
              try {
                const data = new Blob([u8], {type: "application/vnd.ms-excel"});
                writer.onwriteend = () => {
                  try {
                    $q.dialog({title: "Success!", message: msg});
                  } catch(e) { dialogerr(e); }
                };
                writer.onerror = dialogerr;
                writer.write(data);
              } catch(e) { dialogerr(e); }
            }, dialogerr);
          }, dialogerr);
        } catch(e) { dialogerr(e) }
      }, dialogerr);
    }

The page should revert to the old contents.

To test that writing works:

• Click "Save File". You will see a popup with a location:

• Find the file and verify the contents are correct. Run in a new terminal:

find ~/Library/Developer/CoreSimulator -name SheetJSQuasar.xlsx |
  while read x; do echo "$x"; npx xlsx-cli "$x"; done

Since the contents reverted, you should see

SheetJSQuasar
id,content
1,ct1
2,ct2
3,ct3
4,ct4
5,ct5

• Use "Load File" to select pres.numbers again. Wait for the app to refresh.

• Click "Save File", then re-run the command:

find ~/Library/Developer/CoreSimulator -name SheetJSQuasar.xlsx |
  while read x; do echo "$x"; npx xlsx-cli "$x"; done

The contents from pres.numbers should show up now, with a new header row:

SheetJSQuasar
id,content
42,Bill Clinton
43,GeorgeW Bush
44,Barack Obama
45,Donald Trump
46,Joseph Biden

Android

10. Create the Android project:

cd src-cordova
cordova platform add android
cd ..

11. Start the simulator:

quasar dev -m android

If prompted to select an external IP, press Enter.

If the app is blank or not refreshing, delete the app and close the simulator, then restart the development process.

On Windows, the command failed with a Gradle error

Could not find an installed version of Gradle either in Android Studio,
or on your system to install the gradle wrapper. Please include gradle
in your path, or install Android Studio

Gradle (the complete version) must be extracted and the bin folder must be added to the user PATH variable. After adding to PATH, launch a new PowerShell or CMD window and run the command.

To test that reading works:

• Click and drag pres.numbers from a Finder window into the simulator.
• Tap "Load", tap the ≡ icon, tap "Downloads" and select pres.numbers.

To test that writing works:

• Tap "Save File". You will see a popup with a location.

• Pull the file from the simulator and verify the contents:

adb exec-out run-as org.sheetjs.quasar cat files/files/SheetJSQuasar.xlsx > /tmp/SheetJSQuasar.xlsx
npx xlsx-cli /tmp/SheetJSQuasar.xlsx

iOS Device

12. Close all open emulators and simulators.

13. Disconnect any iOS or Android devices connected to the computer.

14. Connect the iOS device to the computer.

15. Open the Xcode project:

open src-cordova/platforms/ios/SheetJSQuasar.xcodeproj

Select "SheetJSQuasar" in the Navigator. In the main pane, select "Signing & Capabilities" and ensure a Team is selected. Save and close the project.

16. Start the dev process:

quasar dev -m ios

If prompted to select an external IP, press Enter.

17. Test the application:

• Press the Home button (or swipe up with one finger) and switch to Safari.
• Download https://docs.sheetjs.com/pres.numbers
• Press the Home button (or swipe up with one finger) and select the SheetJSQuasar app
• Tap the "Load" button, then select "Choose File" and select the downloaded pres.numbers

The table will update with new data.

• Tap "Save File"
• Press the Home button (or swipe up with one finger) and switch to Files.
• Tap < until the main "Browse" window is displayed, then select "On My iPhone"
• Look for the "SheetJSQuasar" folder and tap SheetJSQuasar.xlsx.

If Numbers is installed on the device, it will display the contents of the new file.

Android Device

18. Close all open emulators and simulators.

19. Disconnect any iOS or Android devices connected to the computer.

20. Connect the Android device to the computer.

21. Start the dev process:

quasar dev -m android

If prompted to select an external IP, press Enter.

22. Test the application:

• Press the Home button (or swipe up with one finger) and switch to Browser.
• Download https://docs.sheetjs.com/pres.numbers
• Press the Home button (or swipe up with one finger) and select the SheetJSQuasar app
• Tap the "Load" button, then select "Choose File" and select the downloaded pres.numbers

The table will update with new data.

The "Save File" process will write files. However, Android 30+ requires special methods ("Storage Access Framework") that are not implemented in Quasar.

Footnotes

1. See "File Picker" in the Quasar documentation. ↩

2. See read in "Reading Files" ↩

3. See "SheetJS Data Model" for more details on workbooks, worksheets, and other concepts. ↩

4. See sheet_to_json in "Utilities" ↩

5. See json_to_sheet in "Utilities" ↩

6. See "Workbook Helpers" in "Utilities" for details on book_new and book_append_sheet. ↩

7. See write in "Writing Files" ↩

8. See requestFileSystem in the MDN Web Docs for more details. ↩