docs.sheetjs.com/docz/docs/03-demos/03-desktop/06-reactnative.md

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React Native for Desktop	demos/mobile/index	demos/grid	6	summary Native Components with React

import Tabs from '@theme/Tabs'; import TabItem from '@theme/TabItem';

:::note

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

:::

React Native for Windows + macOS 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

The NodeJS Module can be imported from the main app script. File operations must be written in native code.

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

Windows	macOS

Native Modules

:::caution

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 Modules for effortless integration with native libraries and code.

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 */
  // highlight-next-line
  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 */
    // highlight-next-line
    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);
    // highlight-next-line
    result.Resolve(CryptographicBuffer.EncodeToBase64String(buf));
  } catch(Exception e) { result.Reject(new ReactError { Message = e.Message }); }});
}

REACT_METHOD(PickAndRead);
void PickAndRead(ReactPromise<winrt::hstring> promise) noexcept {
  auto prom = promise;
  /* perform file picker action in the UI thread */
  // highlight-next-line
  context.UIDispatcher().Post([prom = std::move(prom)]()->winrt::fire_and_forget {
    auto p = prom; // promise -> prom -> p dance avoids promise destruction

    /* create file picker */
    FileOpenPicker picker;
    picker.SuggestedStartLocation(PickerLocationId::DocumentsLibrary);
    picker.FileTypeFilter().Append(L".xlsx");
    picker.FileTypeFilter().Append(L".xls");

    /* show file picker */
    // highlight-next-line
    StorageFile file = co_await picker.PickSingleFileAsync();
    if(file == nullptr) { p.Reject("File not Found"); co_return; }

    /* read data and return base64 string */
    auto buf = co_await FileIO::ReadBufferAsync(file);
    // highlight-next-line
    p.Resolve(CryptographicBuffer::EncodeToBase64String(buf));
    co_return;
  });
}

React Native macOS supports Objective-C modules

/* the resolve/reject is projected on the JS side as a Promise */
RCT_EXPORT_METHOD(PickAndRead:(RCTPromiseResolveBlock)resolve rejecter:(RCTPromiseRejectBlock)reject) {
  /* perform file picker action in the UI thread */
  // highlight-next-line
  RCTExecuteOnMainQueue(^{
    /* create file picker */
    NSOpenPanel *panel = [NSOpenPanel openPanel];
    [panel setCanChooseDirectories:NO];
    [panel setAllowsMultipleSelection:NO];
    [panel setMessage:@"Select a spreadsheet to read"];

    /* show file picker */
    // highlight-next-line
    [panel beginWithCompletionHandler:^(NSInteger result){
      if (result == NSModalResponseOK) {
        /* read data and return base64 string */
        NSURL *selected = [[panel URLs] objectAtIndex:0];
        NSFileHandle *hFile = [NSFileHandle fileHandleForReadingFromURL:selected error:nil];
        if(hFile) {
          NSData *data = [hFile readDataToEndOfFile];
          // highlight-next-line
          resolve([data base64EncodedStringWithOptions:0]);
        } else reject(@"read_failure", @"Could not read selected file!", nil);
      } else reject(@"select_failure", @"No file selected!", nil);
    }];
  });
}

Windows Demo

This demo was tested against v0.70.10 on 2023 January 04 in Windows 10.

:::warning

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

The official documentation describes distribution strategies

:::

:::note

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

:::

0. Follow the "Getting Started" guide

:::caution

NodeJS v16 is required. There are OS-specific tools for downgrading:

• nvm-windows Windows
• n Linux, MacOS, WSL, etc.

:::

1. Create a new project using React Native 0.70:

npx react-native init SheetJSWin --template react-native@^0.70.0
cd .\SheetJSWin\

Create the Windows part of the application:

npx react-native-windows-init --no-telemetry --overwrite --language=cs

npx react-native-windows-init --no-telemetry --overwrite

Install library:

npm install --save https://cdn.sheetjs.com/xlsx-latest/xlsx-latest.tgz

To ensure that the app works, launch the app:

npx react-native run-windows --no-telemetry

2. Create the file windows\SheetJSWin\DocumentPicker.cs with the following:

using System;
using System.Threading.Tasks;
using Windows.Security.Cryptography;
using Windows.Storage;
using Windows.Storage.Pickers;
using Microsoft.ReactNative.Managed;

namespace SheetJSWin {
  [ReactModule]
  class DocumentPicker {
    private ReactContext context;
    [ReactInitializer]
    public void Initialize(ReactContext reactContext) { context = reactContext; }

    [ReactMethod("PickAndRead")]
    public async void PickAndRead(IReactPromise<string> result) {
      context.Handle.UIDispatcher.Post(async() => { try {
        var picker = new FileOpenPicker();
        picker.SuggestedStartLocation = PickerLocationId.DocumentsLibrary;
        picker.FileTypeFilter.Add(".xlsx");
        picker.FileTypeFilter.Add(".xls");

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

        var buf = await FileIO.ReadBufferAsync(file);
        result.Resolve(CryptographicBuffer.EncodeToBase64String(buf));
      } catch(Exception e) { result.Reject(new ReactError { Message = e.Message }); }});
    }
  }
}

3. Add the highlighted line to windows\SheetJSWin\SheetJSWin.csproj. Look for the ItemGroup that contains ReactPackageProvider.cs:

<!-- highlight-next-line -->
    <Compile Include="DocumentPicker.cs" />
    <Compile Include="ReactPackageProvider.cs" />
  </ItemGroup>

2. Create the file windows\SheetJSWin\DocumentPicker.h with the following:

#pragma once

#include <winrt/Windows.Storage.Pickers.h>
#include <winrt/Windows.Security.Cryptography.h>
#include "NativeModules.h"

using namespace winrt::Microsoft::ReactNative;
using namespace winrt::Windows::Storage;
using namespace winrt::Windows::Storage::Pickers;
using namespace winrt::Windows::Security::Cryptography;

namespace SheetJSWin {
  REACT_MODULE(DocumentPicker);
  struct DocumentPicker {
    REACT_INIT(Initialize);
    void Initialize(const ReactContext& reactContext) noexcept {
      context = reactContext;
    }

    REACT_METHOD(PickAndRead);
    void PickAndRead(ReactPromise<winrt::hstring> promise) noexcept {
      auto prom = promise;
      context.UIDispatcher().Post([prom = std::move(prom)]()->winrt::fire_and_forget {
        auto p = prom;
        FileOpenPicker picker;
        picker.SuggestedStartLocation(PickerLocationId::DocumentsLibrary);
        picker.FileTypeFilter().Append(L".xlsx");
        picker.FileTypeFilter().Append(L".xls");

        StorageFile file = co_await picker.PickSingleFileAsync();
        if(file == nullptr) { p.Reject("File not Found"); co_return; }

        auto buf = co_await FileIO::ReadBufferAsync(file);
        p.Resolve(CryptographicBuffer::EncodeToBase64String(buf));
        co_return;
      });
    }

    private:
      ReactContext context{nullptr};
  };
}

3. Add the highlighted line to windows\SheetJSWin\ReactPackageProvider.cpp:

#include "ReactPackageProvider.h"
// highlight-next-line
#include "DocumentPicker.h"
#include "NativeModules.h"

Now the native module will be added to the app.

4. Remove App.js and save the following to App.tsx:

import React, { useState, type Node } from 'react';
import { SafeAreaView, ScrollView, StyleSheet, Text, TouchableHighlight, View } from 'react-native';
import { read, utils, version } from 'xlsx';
import { getEnforcing } from 'react-native/Libraries/TurboModule/TurboModuleRegistry';
const DocumentPicker = getEnforcing('DocumentPicker');

const App: () => Node = () => {

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

  return (
    <SafeAreaView style={styles.outer}>
      <Text style={styles.title}>SheetJS × React Native Windows {version}</Text>
      <TouchableHighlight onPress={async() => {
        try {
          const b64 = await DocumentPicker.PickAndRead();
          const wb = read(b64);
          setAoA(utils.sheet_to_json(wb.Sheets[wb.SheetNames[0]], { header: 1 } ));
        } catch(err) { alert(`Error: ${err.message}`); }
      }}><Text style={styles.button}>Click here to Open File!</Text></TouchableHighlight>
      <ScrollView contentInsetAdjustmentBehavior="automatic">
        <View style={styles.table}>{aoa.map((row,R) => (
          <View style={styles.row} key={R}>{row.map((cell,C) => (
            <View style={styles.cell} key={C}><Text>{cell}</Text></View>
          ))}</View>
        ))}</View>
      </ScrollView>
    </SafeAreaView>
  );
};

const styles = StyleSheet.create({
  cell: { flex: 4 },
  row: { flexDirection: 'row', justifyContent: 'space-evenly', padding: 10, backgroundColor: 'white', },
  table: { display: 'flex', flexDirection: 'column', alignItems: 'center', justifyContent: 'center', },
  outer: { marginTop: 32, paddingHorizontal: 24, },
  title: { fontSize: 24, fontWeight: '600', },
  button: { marginTop: 8, fontSize: 18, fontWeight: '400', },
});

export default App;

5. Test the app again:

npx react-native run-windows --no-telemetry

Download https://sheetjs.com/pres.xlsx, then click on "open file". Use the file picker to select the pres.xlsx file and the app will show the data.

macOS Demo

This demo was tested against v0.64.30 on 2023 January 04 in MacOS 12.4

0. Follow the React Native guide for React Native CLI on MacOS.

:::caution

NodeJS v16 is required. There are OS-specific tools for downgrading:

• nvm-windows Windows
• n Linux, MacOS, WSL, etc.

:::

1. Create a new project using React Native 0.64:

npx react-native init SheetJSmacOS --template react-native@^0.64.0
cd SheetJSmacOS

Create the MacOS part of the application:

npx react-native-macos-init --no-telemetry

Install Library:

npm i --save https://cdn.sheetjs.com/xlsx-latest/xlsx-latest.tgz

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.

2. Create the file macos/SheetJSmacOS-macOS/RCTDocumentPicker.h:

#import <React/RCTBridgeModule.h>
@interface RCTDocumentPicker : NSObject <RCTBridgeModule>
@end

Create the file 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

3. Edit the project file macos/SheetJSmacOS.xcodeproj/project.pbxproj.

There are four places where lines must be added:

A) Immediately after /* Begin PBXBuildFile section */

/* Begin PBXBuildFile section */
// highlight-next-line
    4717DC6A28CC499A00A9BE56 /* RCTDocumentPicker.m in Sources */ = {isa = PBXBuildFile; fileRef = 4717DC6928CC499A00A9BE56 /* RCTDocumentPicker.m */; };
    13B07FBC1A68108700A75B9A /* AppDelegate.m in Sources */ = {isa = PBXBuildFile; fileRef = 13B07FB01A68108700A75B9A /* AppDelegate.m */; };

B) Immediately after /* Begin PBXFileReference section */

/* Begin PBXFileReference section */
// highlight-start
    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>"; };
// highlight-end
    008F07F21AC5B25A0029DE68 /* main.jsbundle */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = main.jsbundle; 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";
    };
// highlight-next-line
    514201482437B4B30078DB4F /* SheetJSmacOS-macOS */ = {
      isa = PBXNativeTarget;
...
/* End PBXNativeTarget section */

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

      buildPhases = (
        1A938104A937498D81B3BD3B /* [CP] Check Pods Manifest.lock */,
        381D8A6F24576A6C00465D17 /* Start Packager */,
// highlight-next-line
        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 files, add the highlighted line:

    514201452437B4B30078DB4F /* Sources */ = {
      isa = PBXSourcesBuildPhase;
      buildActionMask = 2147483647;
      files = (
// highlight-next-line
        4717DC6A28CC499A00A9BE56 /* RCTDocumentPicker.m in Sources */,
        514201502437B4B30078DB4F /* ViewController.m in Sources */,
        514201582437B4B40078DB4F /* main.m in Sources */,
        5142014D2437B4B30078DB4F /* AppDelegate.m 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,
      );
// highlight-next-line
      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 = (
// highlight-start
        4717DC6828CC495400A9BE56 /* RCTDocumentPicker.h */,
        4717DC6928CC499A00A9BE56 /* RCTDocumentPicker.m */,
// highlight-end
        5142014A2437B4B30078DB4F /* SheetJSmacOS-macOS */,
        13B07FAE1A68108700A75B9A /* SheetJSmacOS-iOS */,

4. Replace App.js with the following:

import React, { useState, type Node } from 'react';
import { SafeAreaView, ScrollView, StyleSheet, Text, TouchableHighlight, View } from 'react-native';
import { read, utils, version } from 'xlsx';
import { getEnforcing } from 'react-native/Libraries/TurboModule/TurboModuleRegistry';
const DocumentPicker = getEnforcing('DocumentPicker');

const App: () => Node = () => {

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

  return (
    <SafeAreaView style={styles.outer}>
      <Text style={styles.title}>SheetJS × React Native MacOS {version}</Text>
      <TouchableHighlight onPress={async() => {
        try {
          const b64 = await DocumentPicker.PickAndRead();
          const wb = read(b64);
          setAoA(utils.sheet_to_json(wb.Sheets[wb.SheetNames[0]], { header: 1 } ));
        } catch(err) { alert(`Error: ${err.message}`); }
      }}><Text style={styles.button}>Click here to Open File!</Text></TouchableHighlight>
      <ScrollView contentInsetAdjustmentBehavior="automatic">
        <View style={styles.table}>{aoa.map((row,R) => (
          <View style={styles.row} key={R}>{row.map((cell,C) => (
            <View style={styles.cell} key={C}><Text>{cell}</Text></View>
          ))}</View>
        ))}</View>
      </ScrollView>
    </SafeAreaView>
  );
};

const styles = StyleSheet.create({
  cell: { flex: 4 },
  row: { flexDirection: 'row', justifyContent: 'space-evenly', padding: 10, backgroundColor: 'white', },
  table: { display: 'flex', flexDirection: 'column', alignItems: 'center', justifyContent: 'center', },
  outer: { marginTop: 32, paddingHorizontal: 24, },
  title: { fontSize: 24, fontWeight: '600', },
  button: { marginTop: 8, fontSize: 18, fontWeight: '400', },
});

export default App;

5. Test the app:

npx react-native run-macos

Download https://sheetjs.com/pres.xlsx, then click on "open file". Use the file picker to select the pres.xlsx file and the app will show the data.

6. Make a release build:

xcodebuild -workspace macos/SheetJSmacOS.xcworkspace -scheme SheetJSmacOS-macOS -config Release