web api instance method

IDBFactory: databases() method

Available in workers

The databases method of the IDBFactory interface returns a Promise that fulfills with an array of objects containing the name and version of all the available databases.

This is a snapshot of the databases, intended primarily to allow web applications to check what databases have been created — in order to, for example, clean up databases created by earlier versions of application code.

Syntax

databases()

Parameters

None.

Return value

A Promise that fulfills with an array of objects representing a snapshot of the available databases (or rejects with the error/exceptions below).

Each array object has the following properties:

name
- : A database name.
version
- : The database version.

Note that the sequence on the returned objects is undefined.

Exceptions

SecurityError DOMException
- : Thrown if the method is called from an opaque origin or the user has disabled storage.
UnknownError DOMException
- : Thrown if the set of available databases cannot be determined for any reason.

Examples

Create and list databases

This example creates/opens a number of databases. On successful initialization of each database it lists all the available databases.

<pre id="log"></pre>

const logElement = document.querySelector("#log");
function log(text) {
  logElement.innerText = `${logElement.innerText}${text}\n`;
  logElement.scrollTop = logElement.scrollHeight;
}

#log {
  height: 240px;
  overflow: scroll;
  padding: 0.5rem;
  border: 1px solid black;
}

JavaScript

First we define the function that is used to get and log the available databases. This awaits on the promise returned by indexedDB.databases() and then iterates the array and lists the values of each element:

async function getDb() {
  const databases = await indexedDB.databases();
  log("List databases:");
  databases.forEach((element) => {
    log(`name: ${element.name}, version: ${element.version}`);
  });
}

To demonstrate how the above function is used, below we create two databases. For each database, we log just before the database is opened. We also log on successful initialization (or error) and then also log the available databases.

// Create a database named toDoList with default version (1)
const dbName1 = "toDoList";
log(`Opening: ${dbName1}`);
let DBOpenRequest = window.indexedDB.open(dbName1);

DBOpenRequest.addEventListener("error", (event) => {
  log(`Error opening: ${dbName1}`);
  getDb();
});

DBOpenRequest.addEventListener("success", (event) => {
  log(`Initialized: ${dbName1}`);
  getDb();
});

// Create database "AnotherDb"
const dbName2 = "AnotherDb";
log(`Opening ${dbName2}`);
DBOpenRequest = window.indexedDB.open(dbName2, 2);

DBOpenRequest.addEventListener("error", (event) => {
  log(`Error opening: ${dbName2}`);
  getDb();
});

DBOpenRequest.addEventListener("success", (event) => {
  log(`Initialized: ${dbName2}`);
  getDb();
});

Result

The result is shown below. Note that the time taken to get the databases and their order is undefined.

Interactive exampleOpen the canonical MDN source to run this embedded demo.

Specifications

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.