CSV Importer - Tampermonkey script

csv_importer.js

// ==UserScript==
// @name         CSVImporter
// @version      1.0
// @description  Tampermonkey script for importing CSV to web forms. Set desired @match and configure events functions.
// @author       Konrad "Tree" Słotwiński
// @match        https://www.google.com/*
// @grant        GM_setValue
// @grant        GM_getValue
// ==/UserScript==

const CSVI_STORE = "csvi_store";
const CSVI_STATUS = "csvi_status";

const CSVI_EVENT_IMPORT = "csvi_import";
const CSVI_EVENT_RECORD = "csvi_record";
const CSVI_EVENT_STATUS = "csvi_status";

document.addEventListener(CSVI_EVENT_IMPORT, function (e) {
    //Custom event after CSV import
	alert("Import");
	window.location.replace("https://www.google.com/");
});

document.addEventListener(CSVI_EVENT_RECORD, function (e) {
    // Custom event on record import
	alert(`CSVI Importing: (${e.detail.store}) ${e.detail.record}`);
	GM_setValue(CSVI_STATUS, 1);
	window.location.replace("https://www.google.com/");
});

document.addEventListener(CSVI_EVENT_STATUS, function (e) {
    // Custom event on set status
	alert(`CSVI Status: ${e.detail.status}`);
	GM_setValue(CSVI_STATUS, 0);
	window.location.replace("https://www.google.com/");
});

(function () {
	'use strict';
	const data = GM_getValue(CSVI_STORE);
	const status = GM_getValue(CSVI_STATUS);
	if (status) {
		document.dispatchEvent(new CustomEvent(CSVI_EVENT_STATUS, {
			detail: {status: status}
		}));
	} else if (Array.isArray(data) && data.length > 0) {
		document.dispatchEvent(new CustomEvent(CSVI_EVENT_RECORD, {
			detail: {store: data.length, record: data.shift()}
		}));
		GM_setValue(CSVI_STORE, data);
	} else {
		let input = document.createElement("input");
		input.type = "file";
		Object.assign(input.style, {
			display: "block",
			position: "relative",
			"z-index": 10000
		});
		input.addEventListener("input", function (value) {
			let reader = new FileReader();
			reader.readAsText(value.target.files[0]);
			reader.onload = function () {
				GM_setValue(CSVI_STORE, CSVToArray(reader.result));
				document.dispatchEvent(new Event(CSVI_EVENT_IMPORT))
			};
		});
		document.body.prepend(input);
	}
})();

function CSVToArray(data, delimiter = ";") {
	let objPattern = new RegExp(`(\\${delimiter}|\\r?\\n|\\r|^)(?:\"([^\"]*(?:\"\"[^\"]*)*)\"|([^\"\\${delimiter}\\r\\n]*))`, "gi");
	let array = [
		[]
	];
	let arrMatches = null;
	while (arrMatches = objPattern.exec(data)) {
		let strMatchedDelimiter = arrMatches[1];
		let strMatchedValue;
		if (strMatchedDelimiter.length && strMatchedDelimiter !== delimiter) {
			array.push([]);
		}
		if (arrMatches[2]) {
			strMatchedValue = arrMatches[2].replace(new RegExp("\"\"", "g"), "\"");
		} else {
			strMatchedValue = arrMatches[3];
		}
		array[array.length - 1].push(strMatchedValue);
	}
	return array;
}