JS Controller to process CSV File Upload

csvToDatatable.js

import { LightningElement } from 'lwc';

export default class CsvToDatatable extends LightningElement {
  handleFileUpload(event) {
    const files = event.detail.files;

    if (files.length > 0) {
      const file = files[0];
      
      // start reading the uploaded csv file
      this.read(file);
    }
  }
  
  async read(file) {
    try {
      const result = await this.load(file);
      
      // execute the logic for parsing the uploaded csv file
      this.parse(result);
    } catch (e) {
      this.error = e;
    }
  }

  async load(file) {
    return new Promise((resolve, reject) => {
      const reader = new FileReader();

      reader.onload = () => {
        resolve(reader.result);
      };
      reader.onerror = () => {
        reject(reader.error);
      };
      reader.readAsText(file);
    });
  }
}