Upload Data from CSV File Using LWC

// CsvUploadController.apxc
public with sharing class CsvUploadController {
    @AuraEnabled
    public static String uploadCsvFile(String base64Data) {
        try {
            List<Account> accountsToInsert = new List<Account>();
            
            // Decode base64 data
            String csvData = EncodingUtil.base64Decode(base64Data).toString();
            
            // Split CSV rows
            List<String> csvRows = csvData.split('\n');
            
            // Skip header row if present
            Boolean isFirstRow = true;
            
            for (String csvRow : csvRows) {
                if (isFirstRow) {
                    isFirstRow = false;
                    continue;
                }
                
                // Split CSV columns
                List<String> csvColumns = csvRow.split(',');
                
                // Create Account record
                Account acc = new Account(
                    Name = csvColumns[0]
                    // Add other fields as needed
                );
                
                accountsToInsert.add(acc);
            }
            
            // Insert accounts
            if (!accountsToInsert.isEmpty()) {
                insert accountsToInsert;
            }
            
            return 'Success';
        } catch (Exception ex) {
            return 'Error: ' + ex.getMessage();
        }
    }
}

<template>
    <lightning-card title="Upload CSV" icon-name="standard:file">
        <lightning-input type="file" label="Choose CSV File" accept=".csv" onchange={handleFileChange}></lightning-input>
        <lightning-button label="Upload" onclick={uploadCsv} variant="brand"></lightning-button>
    </lightning-card>
</template>

// csvUpload.js
import { LightningElement, api } from 'lwc';
import uploadCsvFile from '@salesforce/apex/CsvUploadController.uploadCsvFile';

export default class CsvUpload extends LightningElement {
    @api recordId;
    csvFile;

    handleFileChange(event) {
        this.csvFile = event.target.files[0];
    }

    uploadCsv() {
        if (this.csvFile) {
            const reader = new FileReader();
            reader.onload = (event) => {
                const base64Data = btoa(event.target.result);
                uploadCsvFile({ base64Data })
                    .then(result => {
                        console.log(result);
                        // Handle success or display a confirmation message
                    })
                    .catch(error => {
                        console.error(error);
                        // Handle error
                    });
            };
            reader.readAsBinaryString(this.csvFile);
        }
    }
}