Awesome
IndexedDB Polyfill
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Use a single, indexable, offline storage API across all desktop and mobile browsers and Node.js.
Even if a browser natively supports IndexedDB, you may still want to use this shim. Some native IndexedDB implementations are very buggy. Others are missing certain features. There are also many minor inconsistencies between different browser implementations of IndexedDB, such as how errors are handled, how transaction timing works, how records are sorted, how cursors behave, etc. Using this shim will ensure consistent behavior across all browsers.
Features
- Optionally adds full IndexedDB support to any web browser that supports WebSQL
- Does nothing if the browser already natively supports IndexedDB
- Can optionally replace native IndexedDB on browsers with buggy implementations
- Works on desktop and mobile devices as well as Node.js (courtesy of websql which sits on top of SQLite3)
- Works on Cordova and PhoneGap via the IndexedDB plug-in (Not recently tested)
- This shim is basically an IndexedDB-to-WebSQL adapter.
- More (though most likely now outdated) details about the project at http://nparashuram.com/IndexedDBShim
Installation
You can download the development or production (minified) script, or install it using NPM.
For Mac, you may need to have CMake installed
for the SQLite3 install to work (See
Tools->How to Install For Command Line Use
) as well as build SQLite3 from
source via npm install --build-from-source
in the node-sqlite3
directory.
Also make sure Python (2.7) is installed.
npm
npm install indexeddbshim
or
yarn add indexeddbshim
Browser set-up
Add the following scripts to your page:
<script src="./node_modules/core-js-bundle/minified.js"></script>
<script src="./node_modules/indexeddbshim/dist/indexeddbshim.min.js"></script>
If you need full Unicode compliance (handling special non-alphanumeric identifiers in store and index names), use the following instead:
<script src="./node_modules/core-js-bundle/minified.js"></script>
<script src="./node_modules/indexeddbshim/dist/indexeddbshim-UnicodeIdentifiers.min.js"></script>
Node set-up
const setGlobalVars = require('indexeddbshim');
global.window = global; // We'll allow ourselves to use `window.indexedDB` or `indexedDB` as a global
setGlobalVars(); // See signature below
ES6 Modules
Bundler for Browser
import setGlobalVars from 'indexeddbshim';
Bundler for Node
import setGlobalVars from 'indexeddbshim/src/node-UnicodeIdentifiers';
// Or without Unicode support
// import setGlobalVars from 'indexeddbshim/src/node';
Usage/API
For the browser scripts, if the browser already natively supports IndexedDB and is not known to be buggy, then the script won't do anything.
Otherwise, assuming WebSQL is available, the script will add the
IndexedDB API
to the browser (unless you use one of the non-invasive files, in which case
setGlobalVars
can be used to optionally add the API to an object of your
choosing; if you also wish Unicode support, you will need to add it yourself).
Either way, you can use IndexedDB just like normal. Here's an example.
setGlobalVars(<winObj or null
>, initialConfig)
In the non-invasive builds (and Node.js), globals are not automatically set. You have the choice to set globals when you wish as well as to set the API on an object of your choosing in place of setting globals.
This is done through setGlobalVars()
(which is otherwise called in the
browser builds automatically with no arguments).
This function defines shimIndexedDB
, indexedDB
, IDBFactory
, etc. on
one of the following objects in order of precedence:
- The passed in
winObj
object if defined window
(for Node, defineglobal.window = global;
)self
(for web workers)global
(for Node)- A new empty object
The initialConfig
argument, if present, should be an object whose keys
are the config properties to set and its values are the config values (see
shimIndexedDB.__setConfig
below).
If you are adding your own window.openDatabase
implementation, supplying
it within initialConfig
(keyed as openDatabase
) will ensure that
shimIndexedDB.__useShim()
is auto-invoked for you if poor IndexedDB
support is detected.
shimIndexedDB.__useShim();
To force IndexedDBShim to shim the browser's native IndexedDB (if our code is not already auto-shimming your browser when detecting poor browser support), add this method call to your script.
On browsers that support WebSQL, this line will completely replace the native IndexedDB implementation with the IndexedDBShim-to-WebSQL implementation.
On browsers that don't support WebSQL, but do support IndexedDB, this line will patch many known problems and add missing features. For example, on Internet Explorer, this will add support for compound keys.
If CFG.addNonIDBGlobals
has been set (e.g., on the initialConfig
argument
of setGlobalVars
), the other non-IndexedDB shims necessitated by this
library will be polyfilled as possible on the chosen "global" (i.e.,
ShimEvent
, ShimCustomEvent
, ShimEventTarget
, ShimDOMException
,
and ShimDOMStringList
). Mostly useful for testing.
If CFG.replaceNonIDBGlobals
is used, it will instead attempt to add,
or if already present, overwrite these globals.
If CFG.fullIDLSupport
has been set, the slow-performing
Object.setPrototypeOf
calls required for full WebIDL compliance will
be used. Probably only needed for testing or environments where full
introspection on class relationships is required.
See this SO topic
shimIndexedDB.__forceClose([dbName], [connIdx], [msg])
The spec anticipates the closing of a database connection with a forced flag.
The spec also mentions some circumstances where this may occur:
A connection may be closed by a user agent in exceptional circumstances, for example due to loss of access to the file system, a permission change, or clearing of the origin’s storage.
Since the latter examples are under the browser's control, this method may be more useful on the server or for unit-testing.
If the first argument, dbName
is missing (or null
or undefined
),
all connections to all databases will be force-closed.
If the second argument, connIdx
is missing (or null
or undefined
),
all connections with the given name will be force-closed. It can
alternatively be an integer representing a 0-based index to indicate a
specific connection to close.
The third argument msg
will be appended to the AbortError
that will be
triggered on the transactions of the connection.
Individual IDBDatabase
database instances can also be force-closed
with a particular message:
db.__forceClose(msg);
shimIndexedDB.__setConnectionQueueOrigin(origin = getOrigin())
Establishes a connectionQueue
for the supplied (or current) origin.
The queue is otherwise only keyed to the detected origin on the loading of the IndexedDBShim script, though this is usually the desired behavior.
shimIndexedDB.__debug(boolean)
The IndexedDB polyfill has sourcemaps enabled, so the polyfill can be debugged even if the minified file is included.
To print out detailed debug messages, add this line to your script:
shimIndexedDB.__debug(true);
shimIndexedDB.__setConfig()
Rather than using globals, a method has been provided to share state across IndexedDBShim modules.
Configuration can be set early in the non-invasive browser and Node builds
via the second argument to setGlobalVars()
(see its definition above).
Its signature (for setting configuration after shimIndexedDB
is created) is:
shimIndexedDB.__setConfig({
property: value, property2: value2, ...otherProperties
});
or:
shimIndexedDB.__setConfig(property, value);
createDOMException(name, message)
A utility for creating a DOMException
instance. Attempts to use any
available native implementation.
Configuration options
The available properties relevant to browser or Node are:
- DEBUG - Boolean (equivalent to calling
shimIndexedDB.__debug(val)
) - cacheDatabaseInstances - Config to ensure that any repeat
IDBFactory.open
call to the same name and version (assuming no deletes or aborts causing rollbacks) will reuse the same SQLiteopenDatabase
instance. - checkOrigin - Boolean on whether to perform origin checks in
IDBFactory
methods (open
,deleteDatabase
,databases
); effectively defaults to true (must be set tofalse
to cancel checks); for Node testing, you will either need to define alocation
global from which the origin value can be found or set this property tofalse
. - UnicodeIDStart and UnicodeIDContinue - Invocation of
createObjectStore
andcreateIndex
calls for validation of key paths. The specification technically allows allIdentifierName
](https://tc39.github.io/ecma262/#prod-IdentifierName) strings, but as this requires a very large regular expression, it is replaced by default with[$A-Z_a-z]
and[$0-9A-Z_a-z]
, respectively. Note that these are and must be expressed as strings, notRegExp
objects. You can use this configuration to change the default to match the spec or as you see fit. In the future we may allow the spec behavior via optional dynamic loading of an internal module. - registerSCA - For data created in 3.* versions of IndexedDBShim to
continue to work with the more recent version of typeson-registry we
are using (specifically its Structured Cloning Algorithm), set this
property to a callback which is passed the current typeson-registry
structured cloning algorithm representation and return its own to be
passed to
typeson.register
. See the library typeson-registry-sca-reverter for a function that can do this and check it for updates if you are using it in case needed to work against new updates of IndexedDBShim. - fullIDLSupport - If set to
true
, the slow-performingObject.setPrototypeOf
calls required for full WebIDL compliance will be used. Probably only needed for testing or environments where full introspection on class relationships is required. See this SO topic - win, Object on which there may be an
openDatabase
method (if any) for WebSQL; Defaults towindow
orself
in the browser and for Node, it is set by default tonode-websql
. If you are intending on adding your ownopenDatabase
implementation, please note that (for the sake of Node), we rely on supplying an additional non-WebSQL-standard callback argument to WebSQLtransaction
orreadTransaction
calls in ournode-websql
fork to allow it to prolong the transaction (to last through our IndexedDB transaction) and to provide rollback functionality. (See https://github.com/axemclion/IndexedDBShim/issues/296, however, for a remaining issue this fix does not currently overcome.) - cursorPreloadPackSize - Number indicating how many records to preload for
caching of (non-multiEntry)
IDBCursor.continue
calls. Defaults to 100. - DEFAULT_DB_SIZE - Used as estimated size argument (in bytes) to
underlying WebSQL
openDatabase
calls. Defaults to4 * 1024 * 1024
or25 * 1024 * 1024
in Safari (apparently necessary due to Safari creating larger files and possibly also due to Safari not completing the storage of all records even after permission is given). Has no effect in Node (usingnode-websql
), and its use in WebSQL-compliant browsers is implementation dependent (the browser may use this information to suggest the use of this quota to the user rather than prompting the user regularly for say incremental 5MB permissions). - useSQLiteIndexes - Whether to create indexes on SQLite tables (and also
whether to try dropping). Indexes can increase file size and slow
performance on tables involving many write operations, but can speed
performance for retrieval. Defaults to
false
. - avoidAutoShim - Where WebSQL is detected but where
indexedDB
is missing or poor support is known (non-Chrome Android or non-Safari iOS9), the shim will be auto-applied withoutshimIndexedDB.__useShim()
. Set this totrue
to avoid forcing the shim for such cases.
The following config are mostly relevant to Node but has bearing on the browser, particularly if one changes the defaults.
- fs - File system module with
unlink
to remove deleted database files. Auto-set by Node distributions. - addNonIDBGlobals - If set to
true
will polyfill the "global" with non-IndexedDB shims created by and sometimes returned publicly by the library. These includeShimEvent
,ShimCustomEvent
,ShimEventTarget
,ShimDOMException
, andShimDOMStringList
. Mostly useful for debugging (and in Node where these are not available by default). - replaceNonIDBGlobals - Similar to
addNonIDBGlobals
but will attempt to add the values unprefixed and overwrite if possible. Mostly for testing. - escapeDatabaseName - Due to the Node implementation's reliance on
node-websql
/node-sqlite3
which create files for each database (and the fact that we haven't provided an option to map filename-safe IDs to arbitrary, user-supplied IndexedDB database names), when the user creates IndexedDB databases, the Node implementation will be subject to the limitations systems can have with filenames. Since IndexedDBShim aims to facilitate code that can work on both the server and client, we have applied some escaping and restrictions by default. The default behavior is to prefix the database name withD_
(to avoid filesystem, SQLite, andnode-sqlite3
problems if the user supplies the IndexedDB-permitted empty string database name), to escape^
which we use as our own generally-filename-supported escape character, to escape NUL (which is also problematic in SQLite identifiers and innode-sqlite3
in general) as^0
, to escape upper-case letters A-Z as^A
,^B
, etc. (since IndexedDB insists on case-sensitivity while file systems often do not), to escape any characters mentioned indatabaseCharacterEscapeList
(as^1
+ a two-hexadecimal-digit-padded sequence), and to throw anError
ifdatabaseNameLengthLimit
is not set tofalse
and is surpassed by the resulting escaped name. You can use thisescapeDatabaseName
callback property to override the default behavior, with the callback accepting a single argument of the user's database name choice and returning your own filename-safe value. Note that we do escape NUL and our own escape character (^
) before passing in the value (for the above-mentioned reasons), though you could unescape and return your own escaped format. While some file systems may not have the other restrictions, you should at a minimum anticipate the possibility for empty strings (since we rely on the result of this function for internal escaping as a SQLite identifier) as well as realize the string":memory:"
will, if unescaped, have a special meaning withnode-sqlite3
. You can make the escaping more lax, e.g., if your file system is case-sensitive, or you could make it more stringent. - unescapeDatabaseName - Not used internally; usable as a convenience method for unescaping strings formatted per our default escaping conventions.
- databaseCharacterEscapeList - When this property and
escapeDatabaseName
are not overridden, the following characters will be escaped by default, even though IndexedDB has no such restrictions, as they are restricted in a number of file systems, even modern, Unicode-supporting ones:0x00-0x1F 0x7F " * / : < > ? \ |
. This property can be overridden with a string that will be converted into an alternate regular expression or supplied withfalse
to disable any character limitations. - databaseNameLengthLimit - When this property and
escapeDatabaseName
are not overridden, an error will be thrown if the escaped filename exceeds the length of 254 characters (the shortest typical modern file length maximum). Provide a number to change the limit or supplyfalse
to disable any length checking. - escapeNFDForDatabaseNames - Boolean defaulting to true on whether to escape NFD-escaping characters to avoid clashes on MacOS which performs NFD on files
- addSQLiteExtension - Boolean on whether to add the
.sqlite
extension to database file names (including__sysdb__
which tracks versions); defaults totrue
- autoName - Boolean config to interpret empty string name as a
cue for creating a database name automatically (introspect on
IDBDatabase.name
to get the actual name used);false
by default
Node-only config:
- sysDatabaseBasePath - Base path for the
__sysdb__(.sqlite)
database file; defaults to__databaseBasePath
unless another value (including the empty string) is given; otherwise is the empty string - databaseBasePath - Base path for user database files; defaults to the empty string
- deleteDatabaseFiles - Deletes physical database file upon
deleteDatabase
(instead of merely emptying). Defaults totrue
. Does not currently delete the database for tracking available databases and versions,__sys__
, if emptied; see #278. - memoryDatabase - String config to cause all opening, deleting, and
listing to be of SQLite in-memory databases; name supplied
by user is still used (including to automatically build a cache since
SQLite does not allow naming of in-memory databases); the name is also
accessible to
IDBFactory.databases()
; causes database name/version tracking to also be within an in-memory database; if set in the browser, avoids normal database name escaping meant for Node compatibility; allowable values include the empty string,":memory:"
, andfile::memory:[?optionalQueryString][#optionalHash]
. See https://sqlite.org/inmemorydb.html and https://sqlite.org/uri.html for more on the function and form of such values
Node config mostly for development debugging:
- sqlBusyTimeout - Integer used by Node WebSQL for SQLite config to set the busy timeout (Defaults to 1000 ms)
- sqlTrace - Callback used by Node WebSQL for SQLite config (Invoked when an SQL statement executes, with a rendering of the statement text)
- sqlProfile - Callback used by Node WebSQL for SQLite config (Invoked every time an SQL statement executes) // Overcoming limitations with node-sqlite3/storing database name on // file systems // https://en.wikipedia.org/wiki/Filename#Reserved_characters_and_words
shimIndexedDB.__getConfig()
For retrieving a config value:
shimIndexedDB.__getConfig(property);
Known Issues
All code has bugs, and this project is no exception. If you find a bug, please let us know about it. Or better yet, send us a fix! Please make sure someone else hasn't already reported the same bug though.
Here is a summary of main known issues to resolve:
blocked
andversionchange
IDBVersionChangeEvent
event support (#2 and #273) across processes/browser windows- Some issues related to task/micro-task timing in Node (for inherent limitations in the browser, see below).
- ImageData storage on Node 14 when used with
node-canvas
- due to this issue
There are a few bugs that are outside of our power to fix. Namely:
Browser rollback
While we do try to rollback the database version in the browser when called for, as we are not able to prolong WebSQL transactions to benefit from the auto-rollback they perform upon encountering an error (nor does WebSQL permit manual ROLLBACK commands so that we could undo the various WebSQL calls we need to make up IndexedDB transactions), we are not able to provide safe rollbacks in the browser. The synchronous WebSQL API was not apparently well supported, at least it is missing in Safari and Chrome, and it would particularly degrade performance in a Node environment.
The special build of websql
that we use does allow such
IndexedDB-spec-compliant (and data-integrity-friendly!) rollback behavior
in Node.
See below on task/micro-task timing for more.
Task/micro-task timing
IndexedDB transactions will timeout so long as there are no detected active requests.
While a single promise delay (a "microtask") is not supposed to be long enough to cause a transaction timeout (and they do not in Node where we have control over extending the transaction), it could possibly occur in our browser implementation.
(Note that chaining multiple promises or having a long-resolving promise will likely cause a transaction to expire even in compliant implementations.)
A setTimeout
timeout of 0
, on the other hand (a full "task"), ought,
for compliant implementations, to be long enough of a time to cause a
time out of the transaction, but in Node where we prolong transactions
long enough to ensure our full chain of asynchronous SQL needed for the
transaction operations is run (as well as ensure complete rollback should
there be an error causing a transaction abort), it may be too short.
We could fix this in Node (where we can have access to a synchronous SQLite API such as https://github.com/grumdrig/node-sqlite unlike on the browser) and ensure transactions finish before the next task (though always after a microtask), but as mentioned above, this would degrade performance particularly on a server (and in the browser, the WebSQL API on which we are relying did not apparently gain support in browsers for the synchronous API).
This test and
this one
demonstrate the expected timeout behavior with regard to setTimeout
or promises and transaction expiration.
Structured Cloning Algorithm
Due to certain challenges in detecting cloneable objects from within JavaScript, there are certain limitations regarding cloning:
- We cannot properly detect
Proxy
to throw upon encountering such non-cloneable objects - Our reliance on
Object.prototype.toString
to detect uncloneable objects can fail if that method is overridden or ifSymbol.toStringTag
is used to change the default reporting of a given "class". - Although they are currently working, we were only able to resolve
Blob
,File
, andFileList
objects synchronously (as required per spec) using the now-deprecatedXMLHttpRequest
synchronous API. - Without a means of transferring
ArrayBuffer
objects in Node, we cannot meet the requirement to fail upon encountering detached binary objects. - They may be other subtleties we have not been able to work around.
We have, however, overcome some cloning issues still faced by browser
implementations, e.g., in Chrome (issue
#698564)
(re: not failing on WeakMap
, WeakSet
, Promise
, and Object.prototype
).
We also have limitations in creating certain objects synchronously, namely, the
one method for creating an image bitmap, createImageBitmap
, returns a
Promise
, so we cannot clone a bona fide image bitmap synchronously so as to
obtain any errors synchronously as expected by the IndexedDB methods involving
cloning.
Node versions 8.9.3 to 9.0.0
Our Mocha test "query multi-entry indexes with hundreds of records" of
IDBIndex/openCursor-spec.js
is failing for these versions. Starting
with 9.1.0, however, the test passes again.
iOS
Due to a bug in WebKit, the
window.indexedDB
property is read-only and cannot be overridden by
IndexedDBShim. There are two possible workarounds for this:
- Use
window.shimIndexedDB
instead ofwindow.indexedDB
- Create an
indexedDB
variable in your closure
By creating a variable named indexedDB
, all the code within that closure
will use the variable instead of the window.indexedDB
property. For
example:
(function () {
// This works on all browsers, and only uses IndexedDBShim as a final fallback
var indexedDB = window.indexedDB || window.mozIndexedDB || // eslint-disable-line no-var -- Older browsers
window.webkitIndexedDB || window.msIndexedDB || window.shimIndexedDB;
// This code will use the native IndexedDB, if it exists, or the shim otherwise
indexedDB.open('MyDatabase', 1);
}());
Windows Phone
This information might be outdated. Reports on current support or fixes welcome.
IndexedDBShim works on Windows Phone via a Cordova/PhoneGap plug-in. There are two plugins available: cordova-plugin-indexedDB and cordova-plugin-indexeddb-async. Both plug-ins rely on a WebSQL-to-SQLite adapter, but there are differences in their implementations. Try them both and see which one works best for your app.
Building
To build the project locally on your computer:
-
Clone this repo If you clone the repository to work against an unstable version, you only need to clone the repository recursively (via
git clone https://github.com/indexeddbshim/indexeddbshim.git --recursive
) if you wish to have the W3C tests available for testing (which unfortunately loads all W3C tests into the "web-platform-tests" subdirectory rather than just the IndexedDB ones). Otherwise, just usegit clone https://github.com/indexeddbshim/indexeddbshim.git
-
Install dev dependencies (and websql for Node)
yarn install
-
Run the build script
npm start
-
Done
The output files will be generated in the dist
directory
Upgrading from previous versions
See Versions for migration information.
Testing
See TESTING.
Resources for IndexedDB
- TrialTool - For experimenting with IndexedDB commands, including predefined examples. (Some examples may depend on others previously being run, even with "Load Pre-Requisites" added, but it is nevertheless useful to avoid boilerplate in testing out commands, in conjunction with the browser developer tools.)
Contributing
Pull requests or Bug reports welcome! See CONTRIBUTING