indexedDB exporter and importer for read it later extension (all tables in one JSON file)

IndexedDB.Exporter.js

// ==UserScript==
// @name         IndexedDB Exporter
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Export all IndexedDB tables into a single JSON file
// @author       You
// @match        *://*/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // Create and append the export button to the body
    const exportButton = document.createElement('button');
    exportButton.textContent = 'Export IndexedDB';
    exportButton.style.position = 'fixed';
    exportButton.style.top = '10px';
    exportButton.style.right = '10px';
    exportButton.style.zIndex = 1000;
    document.body.appendChild(exportButton);

    exportButton.addEventListener('click', exportIndexedDB, false);

    async function exportIndexedDB() {
        const dbName = 'read-it-later';
        const openRequest = indexedDB.open(dbName);

        openRequest.onsuccess = async function(event) {
            const db = event.target.result;
            const exportData = {};

            const objectStoreNames = Array.from(db.objectStoreNames);

            for (const storeName of objectStoreNames) {
                const transaction = db.transaction(storeName, 'readonly');
                const objectStore = transaction.objectStore(storeName);

                const data = await getAllData(objectStore);
                exportData[storeName] = data;
            }

            const jsonString = JSON.stringify(exportData, null, 2);
            const blob = new Blob([jsonString], { type: 'application/json' });

            const link = document.createElement('a');
            link.href = URL.createObjectURL(blob);
            link.download = `${dbName}_export.json`;

            document.body.appendChild(link);
            link.click();

            document.body.removeChild(link);
        };

        openRequest.onerror = function(event) {
            console.error('Error opening database:', event.target.error);
        };
    }

    function getAllData(objectStore) {
        return new Promise((resolve, reject) => {
            const getAllRequest = objectStore.getAll();

            getAllRequest.onsuccess = function(event) {
                resolve(event.target.result);
            };

            getAllRequest.onerror = function(event) {
                reject(event.target.error);
            };
        });
    }
})();

IndexedDB.Importer.js

// ==UserScript==
// @name         IndexedDB Importer
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Import data from a single JSON file into IndexedDB
// @author       You
// @match        *://*/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // Create and append the file input element to the body
    const fileInput = document.createElement('input');
    fileInput.type = 'file';
    fileInput.id = 'fileInput';
    fileInput.style.position = 'fixed';
    fileInput.style.top = '10px';
    fileInput.style.right = '10px';
    fileInput.style.zIndex = 1000;
    document.body.appendChild(fileInput);

    fileInput.addEventListener('change', handleFileSelect, false);

    async function handleFileSelect(event) {
        const file = event.target.files[0];
        const dbName = 'read-it-later';
        const data = await readFileAsJson(file);

        const openRequest = indexedDB.open(dbName);

        openRequest.onsuccess = function(event) {
            const db = event.target.result;
            const existingStores = Array.from(db.objectStoreNames);

            const storesToCreate = Object.keys(data).filter(storeName => !existingStores.includes(storeName));

            if (storesToCreate.length > 0) {
                // Close the current database and upgrade it to create the missing stores
                db.close();

                const newVersion = db.version + 1;
                const upgradeRequest = indexedDB.open(dbName, newVersion);

                upgradeRequest.onupgradeneeded = function(event) {
                    const upgradeDb = event.target.result;
                    storesToCreate.forEach(storeName => {
                        upgradeDb.createObjectStore(storeName, { keyPath: 'id', autoIncrement: true });
                    });
                };

                upgradeRequest.onsuccess = function(event) {
                    const upgradedDb = event.target.result;
                    importData(upgradedDb, data);
                };

                upgradeRequest.onerror = function(event) {
                    console.error('Error upgrading database:', event.target.error);
                };
            } else {
                // All stores already exist, proceed with importing data
                importData(db, data);
            }
        };

        openRequest.onerror = function(event) {
            console.error('Error opening database:', event.target.error);
        };
    }

    function importData(db, data) {
        for (const storeName in data) {
            const transaction = db.transaction(storeName, 'readwrite');
            const objectStore = transaction.objectStore(storeName);

            data[storeName].forEach(item => {
                objectStore.put(item);
            });

            transaction.oncomplete = function() {
                console.log(`Data imported into ${storeName} successfully.`);
            };

            transaction.onerror = function(event) {
                console.error(`Error importing data into ${storeName}:`, event.target.error);
            };
        }
    }

    function readFileAsJson(file) {
        return new Promise((resolve, reject) => {
            const reader = new FileReader();
            reader.onload = function(event) {
                try {
                    const json = JSON.parse(event.target.result);
                    resolve(json);
                } catch (error) {
                    reject(error);
                }
            };
            reader.onerror = function(event) {
                reject(event.target.error);
            };
            reader.readAsText(file);
        });
    }
})();

Read it later extension do not have exporter and importer, read-it-later.

I made these scripts to exporting and importing the data as backup or migration.

As TamperMonkey is not working under chrome-extension domain. the script need to be run in console manually under read it later page.

Suggested revision of L44

const blob = new Blob([jsonString], { type: 'application/json' });
to
const blob = new Blob([jsonString], { type: 'application/json; charset=utf8' });
due to encountered errors with mixed language IndexDBs