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Sheets on the Desktop with React Native

React Native for Windows + macOS1 is a backend for React Native that supports native apps. The Windows backend builds apps for use on Windows 10 / 11, Xbox, and other supported platforms. The macOS backend supports macOS 10.14 SDK

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

This demo uses React Native for Windows + macOS and SheetJS to process spreadsheets. We'll explore how to load SheetJS in a React Native deskktop app and create native modules for selecting and reading files from the computer.

The Windows and macOS demos create apps that look like the screenshots below:

WindowsmacOS

Windows screenshot

macOS screenshot

Tested Deployments

This demo was tested in the following environments:

OS and VersionArchitectureRN PlatformDate
Windows 10win10-x64v0.74.62024-05-28
Windows 11win11-x64v0.74.62024-05-28
Windows 11win11-armv0.74.52024-05-25
MacOS 14.7darwin-x64v0.75.132024-10-26
MacOS 14.5darwin-armv0.73.302024-05-28

This section covers React Native for desktop applications. For iOS and Android applications, check the mobile demo

Telemetry

React Native for Windows + macOS commands include telemetry without proper disclaimer or global opt-out.

The recommended approach for suppressing telemetry is explicitly passing the --no-telemetry flag. The following commands are known to support the flag:

  • Initializing a macOS project with react-native-macos-init
  • Initializing a Windows project with react-native-windows-init
  • Running Windows apps with react-native run-windows

Integration Details​

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

Internal State​

For simplicity, this demo uses an "Array of Arrays"2 as the internal state.

SpreadsheetArray of Arrays

pres.xlsx data

[
  ["Name", "Index"],
  ["Bill Clinton", 42],
  ["GeorgeW Bush", 43],
  ["Barack Obama", 44],
  ["Donald Trump", 45],
  ["Joseph Biden", 46]
]

Each array within the structure corresponds to one row.

The state is initialized with the following snippet:

const [ aoa, setAoA ] = useState(["SheetJS".split(""), "5433795".split("")]);

Updating State​

Starting from a SheetJS worksheet object, sheet_to_json3 with the header option can generate an array of arrays:

/* assuming `wb` is a SheetJS workbook */
function update_state(wb) {
  /* convert first worksheet to AOA */
  const wsname = wb.SheetNames[0];
  const ws = wb.Sheets[wsname];
  const data = utils.sheet_to_json(ws, {header:1});

  /* update state */
  setAoA(data);
}

Displaying Data​

The demos use native View elements from react-native to display data.

Explanation (click to show)

Since some spreadsheets may have empty cells between cells containing data, looping over the rows may skip values!

This example explicitly loops over the row and column indices.

Determining the Row Indices

The first row index is 0 and the last row index is aoa.length - 1. This corresponds to the for loop:

for(var R = 0; R < aoa.length; ++R) {/* ... */}

Determining the Column Indices

The first column index is 0 and the last column index must be calculated from the maximum column index across every row.

Traditionally this would be implemented in a for loop:

var max_col_index = 0;
for(var R = 0; R < aoa.length; ++R) {
  if(!aoa[R]) continue;
  max_col_index = Math.max(max_col_index, aoa[R].length - 1);
}

Array#reduce simplifies this calculation:

const max_col_index = aoa.reduce((C,row) => Math.max(C,row.length), 1) - 1;

Looping from 0 to N-1

Traditionally a for loop would be used:

var data = [];
for(var R = 0; R < max_row; ++R) data[R] = func(R);

For creating an array of React Native components, Array.from should be used:

var children = Array.from({length: max_row}, (_,R) => ( <Row key={R} /> ));

The relevant parts for rendering data are shown below:

import React, { useState, type FC } from 'react';
import { SafeAreaView, ScrollView, Text, View } from 'react-native';

const App: FC = () => {
  const [ aoa, setAoA ] = useState(["SheetJS".split(""), "5433795".split("")]);
  const max_cols = aoa.reduce((acc,row) => Math.max(acc,row.length),1);

  return (
    <SafeAreaView>
      <ScrollView contentInsetAdjustmentBehavior="automatic">
        {/* Table Container */}
        <View>{
          /* Loop over the row indices */
          Array.from({length: aoa.length}, (_, R) => (
            /* Table Row */
            <View key={R}>{
              /* Loop over the column indices */
              Array.from({length: max_cols}, (_, C) => (
                /* Table Cell */
                <View key={C}>
                  <Text>{String(aoa?.[R]?.[C]??"")}</Text>
                </View>
              ))
            }</View>
          ))
        }</View>
      </ScrollView>
    </SafeAreaView>
  );
};
export default App;

Native Modules​

As with the mobile versions of React Native, file operations are not provided by the base SDK. The examples include native code for both Windows and macOS.

The Windows demo assumes some familiarity with C++ / C# and the macOS demo assumes some familiarity with Objective-C.

React Native for Windows + macOS use Turbo Modules4 for native integrations.

The demos define a native module named DocumentPicker.

Reading Files​

The native modules in the demos define a PickAndRead function that will show the file picker, read the file contents, and return a Base64 string.

Only the main UI thread can show file pickers. This is similar to Web Worker DOM access limitations in the Web platform.

Integration

This module can be referenced from the Turbo Module Registry:

import { read } from 'xlsx';
import { getEnforcing } from 'react-native/Libraries/TurboModule/TurboModuleRegistry';
const DocumentPicker = getEnforcing('DocumentPicker');


/* ... in some event handler ... */
async() => {
  const b64 = await DocumentPicker.PickAndRead();
  const wb = read(b64);
  // DO SOMETHING WITH `wb` HERE
}

Native Module

React Native Windows supports C++ and C# projects.

[ReactMethod("PickAndRead")]
public async void PickAndRead(IReactPromise<string> result) {
  /* perform file picker action in the UI thread */
  context.Handle.UIDispatcher.Post(async() => { try {
    /* create file picker */
    var picker = new FileOpenPicker();
    picker.SuggestedStartLocation = PickerLocationId.DocumentsLibrary;
    picker.FileTypeFilter.Add(".xlsx");
    picker.FileTypeFilter.Add(".xls");

    /* show file picker */
    var file = await picker.PickSingleFileAsync();
    if(file == null) throw new Exception("File not found");

    /* read data and return base64 string */
    var buf = await FileIO.ReadBufferAsync(file);
    result.Resolve(CryptographicBuffer.EncodeToBase64String(buf));
  } catch(Exception e) { result.Reject(new ReactError { Message = e.Message }); }});
}

Windows Demo​

There is no simple standalone executable file at the end of the process.

The official documentation describes distribution strategies

React Native Windows supports writing native code in C++ or C#. This demo has been tested against both application types.

  1. Install the development dependencies.

In earlier versions of React Native, NodeJS v16 was required. A tool like nvm-windows should be used to switch the NodeJS version.

Installation Notes (click to show)

When the demo was last tested, a PowerShell script installed dependencies:

Set-ExecutionPolicy Unrestricted -Scope Process -Force;
iex (New-Object System.Net.WebClient).DownloadString('https://aka.ms/rnw-vs2022-deps.ps1');

If any step fails to install, open the dependencies page and expand "Manual setup instructions" to find instructions for manual installation.

Project Setup​

  1. Create a new project using React Native 0.74.1:
npx react-native init SheetJSWin --template [email protected]
cd SheetJSWin
  1. Create the Windows part of the application:
npx react-native-windows-init --no-telemetry --overwrite --language=cs
  1. Install the SheetJS library:
npm i --save https://cdn.sheetjs.com/xlsx-0.20.3/xlsx-0.20.3.tgz
  1. To ensure that the app works, launch the app:
npx react-native run-windows --no-telemetry

When the demo was tested in Windows 11, the run step failed with the message:

The Windows SDK version 10.0.19041.0 was not found

Specific Windows SDK versions can be installed through Visual Studio Installer.

Native Module​

  1. Download DocumentPicker.cs and save to windows\SheetJSWin\DocumentPicker.cs.
iwr -Uri https://docs.sheetjs.com/reactnative/DocumentPicker.cs -OutFile windows/SheetJSWin/DocumentPicker.cs
  1. Edit windows\SheetJSWin\SheetJSWin.csproj to reference DocumentPicker.cs

Search for ReactPackageProvider.cs in the file. There will be one instance. Add the highlighted line just before that instance:

windows\SheetJSWin\SheetJSWin.csproj (add highlighted line)
    <Compile Include="DocumentPicker.cs" />
    <Compile Include="ReactPackageProvider.cs" />
  </ItemGroup>

Now the native module will be added to the app.

Application​

  1. Remove App.js (if it exists) and download App.tsx:
rm App.js
iwr -Uri https://docs.sheetjs.com/reactnative/rnw/App.tsx -OutFile App.tsx
  1. Launch the app again:
npx react-native run-windows --no-telemetry

  1. Download https://docs.sheetjs.com/pres.xlsx.

  2. In the app, click "Click here to Open File!" and use the file picker to select pres.xlsx . The app will refresh and display the data from the file.

macOS Demo​

When the demo was last tested, the official website asserted that the React Native for macOS required React Native 0.71.

The official documentation is out of date.

There exist official react-native-macos releases compatible with RN 0.73

  1. Follow the "Setting up the development environment"5 guide in the React Native documentation for "React Native CLI Quickstart" + "macOS" + "iOS".

Project Setup​

  1. Create a new React Native project using React Native 0.73:
npx -y @react-native-community/cli init SheetJSmacOS --version 0.75
cd SheetJSmacOS

If prompted to install CocoaPods, type Y.

For older versions of React Native, the react-native package included the CLI:

npx -y react-native init SheetJSmacOS --template react-native@^0.73.0

This approach is deprecated as of React Native 0.75.

  1. Create the MacOS part of the application:
npx -y react-native-macos-init --no-telemetry

In some macOS tests, the build failed due to visionos errors:

[!] Failed to load 'React-RCTFabric' podspec:
[!] Invalid `React-RCTFabric.podspec` file: undefined method `visionos' for #<Pod::Specification name="React-RCTFabric">.

This error was resolved by upgrading CocoaPods to 1.15.2:

sudo gem install cocoapods

After upgrading CocoaPods, reinstall the project pods:

cd macos
pod install
cd ..
  1. Install the SheetJS library:
npm i --save https://cdn.sheetjs.com/xlsx-0.20.3/xlsx-0.20.3.tgz
  1. To ensure that the app works, launch the app:
npx react-native run-macos

Close the running app from the dock and close the Metro terminal window.

When the demo was last tested, the app failed with a warning

No bundle URL present.

As this affects the default app, this is a bug in React Native macOS!

The production builds work as expected. If there are errors, click "Dismiss" to dismiss the error, close the app, and make a release build.

Native Module​

  1. Create the file macos/SheetJSmacOS-macOS/RCTDocumentPicker.h with the following contents:
macos/SheetJSmacOS-macOS/RCTDocumentPicker.h
#import <React/RCTBridgeModule.h>
@interface RCTDocumentPicker : NSObject <RCTBridgeModule>
@end
  1. Create the file macos/SheetJSmacOS-macOS/RCTDocumentPicker.m with the following contents:
macos/SheetJSmacOS-macOS/RCTDocumentPicker.m
#import <Foundation/Foundation.h>
#import <React/RCTUtils.h>

#import "RCTDocumentPicker.h"

@implementation RCTDocumentPicker

RCT_EXPORT_MODULE();

RCT_EXPORT_METHOD(PickAndRead:(RCTPromiseResolveBlock)resolve rejecter:(RCTPromiseRejectBlock)reject)
{
  RCTExecuteOnMainQueue(^{
    NSOpenPanel *panel = [NSOpenPanel openPanel];
    [panel setCanChooseDirectories:NO];
    [panel setAllowsMultipleSelection:NO];
    [panel setMessage:@"Select a spreadsheet to read"];

    [panel beginWithCompletionHandler:^(NSInteger result){
      if (result == NSModalResponseOK) {
        NSURL *selected = [[panel URLs] objectAtIndex:0];
        NSFileHandle *hFile = [NSFileHandle fileHandleForReadingFromURL:selected error:nil];
        if(hFile) {
          NSData *data = [hFile readDataToEndOfFile];
          resolve([data base64EncodedStringWithOptions:0]);
        } else reject(@"read_failure", @"Could not read selected file!", nil);
      } else reject(@"select_failure", @"No file selected!", nil);
    }];
  });
}
@end
  1. Edit the project file macos/SheetJSmacOS.xcodeproj/project.pbxproj.

There are four places where lines must be added:

A) Copy the highlighted line and paste under /* Begin PBXBuildFile section */:

/* Begin PBXBuildFile section */
    4717DC6A28CC499A00A9BE56 /* RCTDocumentPicker.m in Sources */ = {isa = PBXBuildFile; fileRef = 4717DC6928CC499A00A9BE56 /* RCTDocumentPicker.m */; };
    3EBD77615057B69A2488153F /* libPods-SheetJSmacOS-macOS.a in Frameworks */ = {isa = PBXBuildFile; fileRef = C28E160785274A8AF9074969 /* libPods-SheetJSmacOS-macOS.a */; };

B) Copy the highlighted lines and paste under /* Begin PBXFileReference section */:

/* Begin PBXFileReference section */
    4717DC6828CC495400A9BE56 /* RCTDocumentPicker.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = RCTDocumentPicker.h; path = "SheetJSMacOS-macOS/RCTDocumentPicker.h"; sourceTree = "<group>"; };
    4717DC6928CC499A00A9BE56 /* RCTDocumentPicker.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; name = RCTDocumentPicker.m; path = "SheetJSMacOS-macOS/RCTDocumentPicker.m"; sourceTree = "<group>"; };

C) The goal is to add a reference to the PBXSourcesBuildPhase block for the macOS target. To determine this, look in the PBXNativeTarget section for a block with the comment SheetJSmacOS-macOS:

/* Begin PBXNativeTarget section */
...
      productType = "com.apple.product-type.application";
    };
    514201482437B4B30078DB4F /* SheetJSmacOS-macOS */ = {
      isa = PBXNativeTarget;
...
/* End PBXNativeTarget section */

Within the block, look for buildPhases and find the hex string for Sources:

    514201482437B4B30078DB4F /* SheetJSmacOS-macOS */ = {
      isa = PBXNativeTarget;
      buildConfigurationList = 5142015A2437B4B40078DB4F /* Build configuration list for PBXNativeTarget "SheetJSmacOS-macOS" */;
      buildPhases = (
        1A938104A937498D81B3BD3B /* [CP] Check Pods Manifest.lock */,
        381D8A6F24576A6C00465D17 /* Start Packager */,
        514201452437B4B30078DB4F /* Sources */,
        514201462437B4B30078DB4F /* Frameworks */,
        514201472437B4B30078DB4F /* Resources */,
        381D8A6E24576A4E00465D17 /* Bundle React Native code and images */,
        3689826CA944E2EF44FCBC17 /* [CP] Copy Pods Resources */,
      );

Search for that hex string (514201452437B4B30078DB4F in our example) in the file and it should show up in a PBXSourcesBuildPhase section. Within the files list, add the highlighted line:

    514201452437B4B30078DB4F /* Sources */ = {
      isa = PBXSourcesBuildPhase;
      buildActionMask = 2147483647;
      files = (
        4717DC6A28CC499A00A9BE56 /* RCTDocumentPicker.m in Sources */,
        514201582437B4B40078DB4F /* main.m in Sources */,
        5142014D2437B4B30078DB4F /* AppDelegate.mm in Sources */,
      );
      runOnlyForDeploymentPostprocessing = 0;
    };

D) The goal is to add file references to the "main group". Search for /* Begin PBXProject section */ and there should be one Project object. Within the project object, look for mainGroup:

/* Begin PBXProject section */
    83CBB9F71A601CBA00E9B192 /* Project object */ = {
      isa = PBXProject;
...
        Base,
      );
      mainGroup = 83CBB9F61A601CBA00E9B192;
      productRefGroup = 83CBBA001A601CBA00E9B192 /* Products */;
...
/* End PBXProject section */

Search for that hex string (83CBB9F61A601CBA00E9B192 in our example) in the file and it should show up in a PBXGroup section. Within children, add the highlighted lines:

    83CBB9F61A601CBA00E9B192 = {
      isa = PBXGroup;
      children = (
        4717DC6828CC495400A9BE56 /* RCTDocumentPicker.h */,
        4717DC6928CC499A00A9BE56 /* RCTDocumentPicker.m */,
        5142014A2437B4B30078DB4F /* SheetJSmacOS-macOS */,
  1. To ensure that the app still works, launch the app again:
npx react-native run-macos

If the app runs but no window is displayed, clear caches and try again:

npx react-native clean --include metro,watchman
npx react-native run-macos

Close the running app from the dock and close the Metro terminal window.

Application​

  1. Download App.tsx and replace the file in the project:
curl -LO https://docs.sheetjs.com/reactnative/rnm/App.tsx
  1. Download https://docs.sheetjs.com/pres.xlsx to the Downloads folder.

Development​

In some test runs, the development mode app failed with a "bundle URL" error:

No bundle URL present.

The "Production" section section covers release builds and tests.

  1. Launch the app again:
npx react-native run-macos
  1. Click "Click here to Open File!" and use the file picker to select pres.xlsx from the Downloads folder.

The app will refresh and display the data from the file.

Close the running app from the dock and close the Metro terminal window.

Production​

  1. Remove all existing SheetJSmacOS.app release builds. They will be stored in the ~/Library/Developer/Xcode/DerivedData folder.
find ~/Library/Developer/Xcode/DerivedData -name SheetJSmacOS.app | grep Release | while read x; do rm -rf "$x"; done
  1. Make a release build:
xcodebuild -workspace macos/SheetJSmacOS.xcworkspace -scheme SheetJSmacOS-macOS -config Release

When the demo was last tested, the path to the generated app was displayed in the terminal. Search for Release/SheetJSmacOS.app and look for touch -c:

Sample result when searching for 'touch -c'
    /usr/bin/touch -c /Users/sheetjs/Library/Developer/Xcode/DerivedData/SheetJSmacOS-abcdefghijklmnopqrstuvwxyzab/Build/Products/Release/SheetJSmacOS.app

If there are no instances, the app path can be found in the DerivedData folder:

find ~/Library/Developer/Xcode/DerivedData -name SheetJSmacOS.app | grep Release
  1. Run the release app:
open -a "$(find ~/Library/Developer/Xcode/DerivedData -name SheetJSmacOS.app | grep Release | head -n 1)"
  1. Click "Click here to Open File!" and use the file picker to select pres.xlsx from the Downloads folder.

The app will refresh and display the data from the file.

Footnotes​

  1. The official website covers both platforms, but there are separate repositories for Windows and macOS ↩

  2. See "Array of Arrays" in the API reference ↩

  3. See "Array Output" in "Utility Functions" ↩

  4. See "Turbo Native Modules" in the React Native documentation. ↩

  5. See "Setting up the development environment" in the React Native documentation. Select the "React Native CLI Quickstart" tab and choose the Development OS "macOS" and the Target OS "iOS". ↩