How to save an excel file using react-query with react- native - fs ?

Step 1: Install Required Packages

First, ensure your project has the necessary packages installed: react-native-fs and react-query. If not installed, you can install them using the following commands:

bash
npm install react-native-fs
npm install react-query

Additionally, if you need to handle Excel files, you will also need a library such as xlsx that can process Excel files:

bash
npm install xlsx

Step 2: Create a Custom Hook Using React Query

Next, create a custom hook that uses React Query's useMutation to handle the Excel file saving logic. useMutation is ideal for performing side effects like creating, updating, or deleting data.

javascript
import { useMutation } from 'react-query';
import RNFS from 'react-native-fs';
import XLSX from 'xlsx';

function useSaveExcel() {
  return useMutation(async (data) => {
    // Convert data to a worksheet
    const ws = XLSX.utils.json_to_sheet(data);
    const wb = XLSX.utils.book_new();
    XLSX.utils.book_append_sheet(wb, ws, "Sheet1");

    // Generate the Excel file content
    const wbout = XLSX.write(wb, { type: 'binary' });

    // Get the file path
    const path = `${RNFS.DocumentDirectoryPath}/myExcelFile.xlsx`;

    // Write the binary string to the file
    await RNFS.writeFile(path, wbout, 'ascii');
    return path;
  });
}

Step 3: Use the Custom Hook in a Component

In a React component, you can use the useSaveExcel hook created above to save Excel files.

javascript
import React from 'react';
import { Button } from 'react-native';

function MyComponent() {
  const { mutate: saveExcel, isSuccess, data } = useSaveExcel();

  const handleSave = () => {
    const myData = [{ name: "John", age: 30 }, { name: "Jane", age: 25 }];
    saveExcel(myData);
  };

  return (
    <>
      <Button title="Save Excel" onPress={handleSave} />
      {isSuccess && <Text>Excel saved to: {data}</Text>}
    </>
  );
}

In this component, when the user clicks the 'Save Excel' button, the handleSave function is triggered, passing sample data to saveExcel. If the save is successful, a success message and the file path will be displayed.

Thus, you can effectively generate and save Excel files in your React Native application by combining the react-native-fs and xlsx libraries, while leveraging React Query to manage the asynchronous logic and state of data saving.