fake-indexeddb

This is a pure JS in-memory implementation of the IndexedDB 2.0 API (which technically still is a draft, but is probably not going to substantially change). Its main utility is for testing IndexedDB-dependent code in Node.js.

Installation

npm install fake-indexeddb

Use

Functionally, it works exactly like IndexedDB except data is not persisted to disk.

var indexedDB = require("fake-indexeddb");
var IDBKeyRange = require("fake-indexeddb/lib/FDBKeyRange");

var request = indexedDB.open("test", 3);
request.onupgradeneeded = function () {
    var db = request.result;
    var store = db.createObjectStore("books", {keyPath: "isbn"});
    store.createIndex("by_title", "title", {unique: true});

    store.put({title: "Quarry Memories", author: "Fred", isbn: 123456});
    store.put({title: "Water Buffaloes", author: "Fred", isbn: 234567});
    store.put({title: "Bedrock Nights", author: "Barney", isbn: 345678});
}
request.onsuccess = function (event) {
    var db = event.target.result;

    var tx = db.transaction("books");

    tx.objectStore("books").index("by_title").get("Quarry Memories").addEventListener("success", function (event) {
        console.log("From index:", event.target.result);
    });
    tx.objectStore("books").openCursor(IDBKeyRange.lowerBound(200000)).onsuccess = function (event) {
        var cursor = event.target.result;
        if (cursor) {
            console.log("From cursor:", cursor.value);
            cursor.continue();
        }
    };
    tx.oncomplete = function () {
        console.log("All done!");
    };
};

When importing individual classes directly (like var IDBKeyRange = require("fake-indexeddb/lib/FDBKeyRange"); above), file names of all the objects are like the normal IndexedDB ones except with F replacing I, e.g. FDBIndex instead of IDBIndex.

Quality

Here's a comparison of fake-indexeddb and real browser IndexedDB implementations on the W3C IndexedDB test suite as of April 28, 2017:

Implementation	Percentage of files that pass completely
Firefox 53	93%
Chrome 57	92%
fake-indexeddb 2.0	88%
Safari 10	83%
Edge 14	59%

For browsers, I ran http://w3c-test.org/tools/runner/index.html and counted the passes. For fake-indexeddb, I ran npm run test-w3c.

88% is pretty good, right? Especially considering that fake-indexeddb runs in Node.js where failure is guaranteed for tests involving browser APIs like Web Workers. There are definitley still some weak points of fake-indexeddb, all described in src/test/web-platform-tests/run-all.js. Your app will probably run fine, though.

Potential applications:

1. Use as a mock database in unit tests.

2. Use the same API in Node.js and in the browser.

3. Support IndexedDB in old or crappy browsers.

4. Somehow use it within a caching layer on top of IndexedDB in the browser, since IndexedDB can be kind of slow.

5. Abstract the core database functions out, so what is left is a shell that allows the IndexedDB API to easily sit on top of many different backends.

6. Serve as a playground for experimenting with IndexedDB.

License

Apache 2.0