docs.sheetjs.com/01-reactnative.md at 19dfa5712057e11351a2274c8cfddf700a9488ff

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2023-04-30 21:27:02 -04:00

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React Native

demos/static/index

demos/desktop/index

summary
React + Native Rendering

import current from '/version.js'; import Tabs from '@theme/Tabs'; import TabItem from '@theme/TabItem'; import CodeBlock from '@theme/CodeBlock';

The NodeJS Module can be imported from the main App.js entrypoint or any script in the project.

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

iOS	Android

"Fetching Remote Data" uses the built-in fetch to download and parse remote workbook files.

"Native Libraries" uses native libraries to read and write files in the local device.

:::caution

Before reading this demo, follow the official React Native CLI Guide!

Development Environment Guide: https://reactnative.dev/docs/environment-setup

Follow the instructions for iOS (requires macOS) and for Android. They will cover installation and system configuration. You should be able to build and run a sample app in the Android and the iOS (if applicable) simulators.

:::

Fetching Remote Data

:::info

React Native 0.72.0 will support binary data with fetch. For older versions, a native library can provide support.

:::

React Native 0.72.0 will support binary data with fetch:

/* fetch data into an ArrayBuffer */
const ab = await (await fetch("https://sheetjs.com/pres.numbers")).arrayBuffer();
/* parse data */
const wb = XLSX.read(ab);

Fetch Demo

The following demo uses react-native-table-component to display the first worksheet in a simple table.

:::note

This demo was tested on an Intel Mac on 2023 April 24 with RN 0.72.0-rc.1.

The iOS simulator runs iOS 16.2 on an iPhone SE (3rd generation).

:::

Create project:

npx react-native init SheetJSRNFetch --version="0.72.0-rc.1"

Install shared dependencies:

{\ cd SheetJSRNFetch curl -LO https://oss.sheetjs.com/assets/img/logo.png npm i -S https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz npm i -S react-native-table-component@1.2.0 @types/react-native-table-component}

Refresh iOS project by running pod install from the ios subfolder:

cd ios; pod install; cd ..

Download App.tsx and replace:

curl -LO https://docs.sheetjs.com/reactnative/App.tsx

iOS Testing

Start the iOS emulator:

npx react-native run-ios

When opened, the app should look like the "Before" screenshot below. After tapping "Import data from a spreadsheet", the app should show new data:

Before	After

Android Testing

Start the Android emulator:

npx react-native run-android

:::note

When this demo was last tested, the simulator failed with the message

Unable to load script. Make sure you're either Running Metro ...

The workaround is to launch Metro directly:

npx react-native start

Press a in the terminal window and Metro will try to reload the app.

:::

When opened, the app should look like the "Before" screenshot below. After tapping "Import data from a spreadsheet", the app should show new data:

Before	After

Native Libraries

:::warning

React Native does not provide a native file picker or a method for reading and writing data from documents on the devices. A third-party library must be used.

Since React Native internals change between releases, libraries may only work with specific versions of React Native. Project documentation should be consulted before picking a library.

:::

The following table lists tested file plugins. "OS" lists tested platforms ("A" for Android and "I" for iOS). "Copy" indicates whether an explicit copy is needed (file picker copies to cache directory and file plugin reads cache).

File system Plugin	File Picker Plugin	OS	Copy
`react-native-file-access`	`react-native-document-picker`	`AI`
`react-native-blob-util`	`react-native-document-picker`	`AI`	YES
`rn-fetch-blob`	`react-native-document-picker`	`AI`	YES
`react-native-fs`	`react-native-document-picker`	`AI`	YES
`expo-file-system`	`expo-document-picker`	`I`	YES

RN File Picker

The following libraries have been tested:

`react-native-document-picker`

Selecting a file (click to show)

When a copy is not needed:

import { pickSingle } from 'react-native-document-picker';

const f = await pickSingle({allowMultiSelection: false, mode: "open" });
const path = f.uri; // this path can be read by RN file plugins

When a copy is needed:

import { pickSingle } from 'react-native-document-picker';

const f = await pickSingle({allowMultiSelection: false, copyTo: "cachesDirectory", mode: "open" });
const path = f.fileCopyUri; // this path can be read by RN file plugins

`expo-document-picker`

Selecting a file (click to show)

When using DocumentPicker.getDocumentAsync, enable copyToCacheDirectory:

import * as DocumentPicker from 'expo-document-picker';

const result = await DocumentPicker.getDocumentAsync({
  // highlight-next-line
  copyToCacheDirectory: true,
  type: ['application/vnd.ms-excel', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet']
});
const path = result.uri;

RN File Plugins

The following libraries have been tested:

`react-native-blob-util` and `rn-fetch-blob`

:::note Historical Context

The react-native-fetch-blob project was archived in 2019. At the time, there were a number of project forks. The maintainers blessed the rn-fetch-blob fork as the spiritual successor.

react-native-blob-util is an active fork of rn-fetch-blob

When this demo was last tested, rn-fetch-blob and react-native-blob-util both worked with the tested iOS and Android SDK versions. The APIs are identical for the purposes of working with files.

:::

The ascii type returns an array of numbers corresponding to the raw bytes. A Uint8Array from the data is compatible with the buffer type.

Reading and Writing snippets (click to show)

The snippets use rn-fetch-blob. To use react-native-blob-util, change the import statements to load the module.

Reading Data

import * as XLSX from "xlsx";
import RNFetchBlob from 'rn-fetch-blob'; // or react-native-blob-util
const { readFile } = RNFetchBlob.fs;

const res = await readFile(path, 'ascii');
const wb = XLSX.read(new Uint8Array(res), {type:'buffer'});

:::caution

On iOS, the URI from react-native-document-picker must be massaged:

import { pickSingle } from 'react-native-document-picker';
import RNFetchBlob from 'rn-fetch-blob'; // or react-native-blob-util
const { readFile, dirs: { DocumentDir } } = RNFetchBlob.fs;

const f = await pickSingle({
// highlight-start
  // Instruct the document picker to copy file to Documents directory
  copyTo: "documentDirectory",
// highlight-end
  allowMultiSelection: false, mode: "open" });
// highlight-start
// `f.uri` is the original path and `f.fileCopyUri` is the path to the copy
let path = f.fileCopyUri;
// iOS workaround
if (Platform.OS === 'ios') path = path.replace(/^.*\/Documents\//, DDP + "/");
// highlight-end

const res = await readFile(path, 'ascii');

:::

Writing Data

import * as XLSX from "xlsx";
import RNFetchBlob from 'rn-fetch-blob'; // or react-native-blob-util
const { writeFile, readFile, dirs:{ DocumentDir } } = RNFetchBlob.fs;

const wbout = XLSX.write(wb, {type:'buffer', bookType:"xlsx"});
const file = DocumentDir + "/sheetjsw.xlsx";
const res = await writeFile(file, Array.from(wbout), 'ascii');

`react-native-file-access`

The base64 encoding returns strings compatible with the base64 type:

Reading and Writing snippets (click to show)

Reading Data

import * as XLSX from "xlsx";
import { FileSystem } from "react-native-file-access";

const b64 = await FileSystem.readFile(path, "base64");
/* b64 is a Base64 string */
const workbook = XLSX.read(b64, {type: "base64"});

Writing Data

import * as XLSX from "xlsx";
import { Dirs, FileSystem } from "react-native-file-access";
const DDP = Dirs.DocumentDir + "/";

const b64 = XLSX.write(workbook, {type:'base64', bookType:"xlsx"});
/* b64 is a Base64 string */
await FileSystem.writeFile(DDP + "sheetjs.xlsx", b64, "base64");

`react-native-fs`

The ascii encoding returns binary strings compatible with the binary type:

Reading and Writing snippets (click to show)

Reading Data

import * as XLSX from "xlsx";
import { readFile } from "react-native-fs";

const bstr = await readFile(path, "ascii");
/* bstr is a binary string */
const workbook = XLSX.read(bstr, {type: "binary"});

Writing Data

import * as XLSX from "xlsx";
import { writeFile, DocumentDirectoryPath } from "react-native-fs";

const bstr = XLSX.write(workbook, {type:'binary', bookType:"xlsx"});
/* bstr is a binary string */
await writeFile(DocumentDirectoryPath + "/sheetjs.xlsx", bstr, "ascii");

`expo-file-system`

:::caution

Some Expo APIs return URI that cannot be read with expo-file-system. This will manifest as an error:

Unsupported scheme for location '...'

The expo-document-picker snippet makes a local copy.

:::

The EncodingType.Base64 encoding is compatible with base64 type.

Reading and Writing snippets (click to show)

Reading Data

Calling FileSystem.readAsStringAsync with FileSystem.EncodingType.Base64 encoding returns a promise resolving to a string compatible with base64 type:

import * as XLSX from "xlsx";
import * as FileSystem from 'expo-file-system';

const b64 = await FileSystem.readAsStringAsync(uri, { encoding: FileSystem.EncodingType.Base64 });
const workbook = XLSX.read(b64, { type: "base64" });

Writing Data

The FileSystem.EncodingType.Base64 encoding accepts Base64 strings:

import * as XLSX from "xlsx";
import * as FileSystem from 'expo-file-system';

const b64 = XLSX.write(workbook, {type:'base64', bookType:"xlsx"});
/* b64 is a Base64 string */
await FileSystem.writeAsStringAsync(FileSystem.documentDirectory + "sheetjs.xlsx", b64, { encoding: FileSystem.EncodingType.Base64 });

Demo

:::note

This demo was tested on an Intel Mac on 2023 April 30 with RN 0.72.0-rc.1.

The iOS simulator runs iOS 16.2 on an iPhone 14.

The Android simulator runs Android 12 (S) Platform 31 on a Pixel 5.

:::

:::warning

There are many moving parts and pitfalls with React Native apps. It is strongly recommended to follow the official React Native tutorials for iOS and Android before approaching this demo. Details like creating an Android Virtual Device are not covered here.

:::

This example tries to separate the library-specific functions.

Create project:

npx react-native init SheetJSRN --version="0.72.0-rc.1"

Install shared dependencies:

{\ cd SheetJSRN curl -LO https://oss.sheetjs.com/assets/img/logo.png npm i -S https://cdn.sheetjs.com/xlsx-${current}/xlsx-${current}.tgz npm i -S react-native-table-component@1.2.0 react-native-document-picker@8.2.0}

Refresh iOS project by running pod install from the ios subfolder:

cd ios
pod install
cd ..

Download index.js and replace:

curl -LO https://docs.sheetjs.com/mobile/index.js

Start the iOS emulator:

npx react-native run-ios

You should see the skeleton app:

Pick a filesystem library for integration:

Install react-native-blob-util dependency:

npm i -S react-native-blob-util@0.17.1

Add the highlighted lines to index.js:

import { Table, Row, Rows, TableWrapper } from 'react-native-table-component';

// highlight-start
import { read, write } from 'xlsx';
import { pickSingle } from 'react-native-document-picker';
import { Platform } from 'react-native';
import RNFetchBlob from 'react-native-blob-util';

async function pickAndParse() {
  /* rn-fetch-blob / react-native-blob-util need a copy */
  const f = await pickSingle({allowMultiSelection: false, copyTo: "documentDirectory", mode: "open" });
  let path = f.fileCopyUri;
  if (Platform.OS === 'ios') path = path.replace(/^.*\/Documents\//, RNFetchBlob.fs.dirs.DocumentDir + "/");
  const res = await (await fetch(path)).arrayBuffer(); // RN >= 0.72
  // const res = await RNFetchBlob.fs.readFile(path, 'ascii'); // RN < 0.72
  return read(new Uint8Array(res), {type: 'buffer'});
}

async function writeWorkbook(wb) {
  const wbout = write(wb, {type:'buffer', bookType:"xlsx"});
  const file = RNFetchBlob.fs.dirs.DocumentDir + "/sheetjsw.xlsx";
  await RNFetchBlob.fs.writeFile(file, Array.from(wbout), 'ascii');
  return file;
}
// highlight-end

const make_width = ws => {

Install react-native-file-access dependency:

npm i -S react-native-file-access@2.6.0

Add the highlighted lines to index.js:

import { Table, Row, Rows, TableWrapper } from 'react-native-table-component';

// highlight-start
import { read, write } from 'xlsx';
import { pickSingle } from 'react-native-document-picker';
import { Platform } from 'react-native';
import { Dirs, FileSystem } from 'react-native-file-access';

async function pickAndParse() {
  /* react-native-file-access in RN < 0.72 does not need a copy */
  //const f = await pickSingle({allowMultiSelection: false, mode: "open" });
  //const res = await FileSystem.readFile(f.uri, "base64");
  //return read(res, {type: 'base64'});
  /* react-native-file-access in RN >= 0.72 needs a copy */
  const f = await pickSingle({allowMultiSelection: false, copyTo: "documentDirectory", mode: "open" });
  let path = f.fileCopyUri;
  const res = await (await fetch(path)).arrayBuffer();
  return read(new Uint8Array(res), {type: 'buffer'});
}

async function writeWorkbook(wb) {
  const wbout = write(wb, {type:'base64', bookType:"xlsx"});
  const file = Dirs.DocumentDir + "/sheetjsw.xlsx";
  await FileSystem.writeFile(file, wbout, "base64");
  return file;
}
// highlight-end

const make_width = ws => {

Install rn-fetch-blob dependency:

npm i -S rn-fetch-blob@0.12.0

Add the highlighted lines to index.js:

import { Table, Row, Rows, TableWrapper } from 'react-native-table-component';

// highlight-start
import { read, write } from 'xlsx';
import { pickSingle } from 'react-native-document-picker';
import { Platform } from 'react-native';
import RNFetchBlob from 'rn-fetch-blob';

async function pickAndParse() {
  /* rn-fetch-blob / react-native-blob-util need a copy */
  const f = await pickSingle({allowMultiSelection: false, copyTo: "documentDirectory", mode: "open" });
  let path = f.fileCopyUri;
  if (Platform.OS === 'ios') path = path.replace(/^.*\/Documents\//, RNFetchBlob.fs.dirs.DocumentDir + "/");
  const res = await (await fetch(path)).arrayBuffer(); // RN >= 0.72
  // const res = await RNFetchBlob.fs.readFile(path, 'ascii'); // RN < 0.72
  return read(new Uint8Array(res), {type: 'buffer'});
}

async function writeWorkbook(wb) {
  const wbout = write(wb, {type:'buffer', bookType:"xlsx"});
  const file = RNFetchBlob.fs.dirs.DocumentDir + "/sheetjsw.xlsx";
  await RNFetchBlob.fs.writeFile(file, Array.from(wbout), 'ascii');
  return file;
}
// highlight-end

const make_width = ws => {

Install react-native-fs dependency:

npm i -S react-native-fs@2.20.0

Add the highlighted lines to index.js:

import { Table, Row, Rows, TableWrapper } from 'react-native-table-component';

// highlight-start
import { read, write } from 'xlsx';
import { pickSingle } from 'react-native-document-picker';
import { writeFile, readFile, DocumentDirectoryPath } from 'react-native-fs';

async function pickAndParse() {
  /* react-native-fs needs a copy */
  const f = await pickSingle({allowMultiSelection: false, copyTo: "cachesDirectory", mode: "open" });
  const bstr = await readFile(f.fileCopyUri, 'ascii');
  return read(bstr, {type:'binary'});
}

async function writeWorkbook(wb) {
  const wbout = write(wb, {type:'binary', bookType:"xlsx"});
  const file = DocumentDirectoryPath + "/sheetjsw.xlsx";
  await writeFile(file, wbout, 'ascii');
  return file;
}
// highlight-end

const make_width = ws => {

:::warning

At the time of testing, Expo did not support RN 0.72 . The project should be created with React Native 0.67.2:

npx react-native init SheetJSRN --version="0.67.2"

:::

Install expo-file-system and expo-document-picker dependencies:

npx install-expo-modules
npm i -S expo-file-system expo-document-picker

Add the highlighted lines to index.js:

import { Table, Row, Rows, TableWrapper } from 'react-native-table-component';

// highlight-start
import { read, write } from 'xlsx';
import { getDocumentAsync } from 'expo-document-picker';
import { documentDirectory, readAsStringAsync, writeAsStringAsync } from 'expo-file-system';

async function pickAndParse() {
  const result = await getDocumentAsync({copyToCacheDirectory: true});
  const path = result.uri;
  const res = await readAsStringAsync(path, { encoding: "base64" });
  return read(res, {type: 'base64'});
}

async function writeWorkbook(wb) {
  const wbout = write(wb, {type:'base64', bookType:"xlsx"});
  const file = documentDirectory + "sheetjsw.xlsx";
  await writeAsStringAsync(file, wbout, { encoding: "base64" });
  return file;
}
// highlight-end

const make_width = ws => {

Refresh the app:

cd ios
pod install
cd ..

Once refreshed, the development process must be restarted:

npx react-native run-ios

iOS Testing

The app can be tested with the following sequence in the simulator:

Download https://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 SheetJSRN app
Click "Import data" and select pres:

Once selected, the screen should refresh with new contents:

Click "Export data". You will see a popup with a location:

Find the file and verify the contents are correct:

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

Once testing is complete, stop the simulator and the development process.

Android Testing

There are no Android-specific steps. Emulator can be started with:

npx react-native run-android

The app can be tested with the following sequence in the simulator:

Download https://sheetjs.com/pres.numbers
Click and drag pres.numbers from a Finder window into the simulator.
Click "Import data" and select pres.numbers:

Once selected, the screen should refresh with new contents:

Click "Export data". You will see a popup with a location:

Pull the file from the simulator and verify the contents:

adb exec-out run-as com.sheetjsrn cat files/sheetjsw.xlsx > /tmp/sheetjsw.xlsx
npx xlsx-cli /tmp/sheetjsw.xlsx

21 KiB Raw Blame History

Fetching Remote Data

Fetch Demo

Native Libraries

RN File Picker

react-native-document-picker

expo-document-picker

RN File Plugins

react-native-blob-util and rn-fetch-blob

react-native-file-access

react-native-fs

expo-file-system

Demo

21 KiB

Raw Blame History

`react-native-document-picker`

`expo-document-picker`

`react-native-blob-util` and `rn-fetch-blob`

`react-native-file-access`

`react-native-fs`

`expo-file-system`