Dexie is a wrapper for IndexedDB, a low-level API for client-side storage of significant amounts of structured data, including files/blobs. Dexie simplifies the use of IndexedDB by providing a more developer-friendly API and additional features such as versioning, transactions, and observability.
Database Initialization
This code initializes a new Dexie database named 'MyDatabase' and defines a schema for a 'friends' table with auto-incrementing primary key 'id' and indexed fields 'name' and 'age'.
const db = new Dexie('MyDatabase');
db.version(1).stores({
friends: '++id,name,age'
});Adding Data
This code adds a new record to the 'friends' table with the name 'John' and age 25.
db.friends.add({name: 'John', age: 25});Querying Data
This code queries the 'friends' table for all records where the age is below 30 and logs the results to the console.
db.friends.where('age').below(30).toArray().then(friends => {
console.log(friends);
});Updating Data
This code updates the record with primary key 1 in the 'friends' table, setting the age to 26.
db.friends.update(1, {age: 26});Deleting Data
This code deletes the record with primary key 1 from the 'friends' table.
db.friends.delete(1);The 'idb' package is a small library that provides a more modern and promise-based API for IndexedDB. It is simpler and lighter than Dexie but does not offer as many advanced features such as observability and complex querying.
LocalForage is a library that provides a simple API for storing data in various storage backends, including IndexedDB, WebSQL, and localStorage. It is more versatile in terms of storage options but does not offer the same level of IndexedDB-specific features and optimizations as Dexie.
PouchDB is a JavaScript database that syncs with CouchDB. It provides a more comprehensive solution for offline-first applications with synchronization capabilities. However, it is heavier and more complex compared to Dexie, which is focused solely on IndexedDB.
Dexie.js is a wrapper library for indexedDB - the standard database in the browser. http://dexie.org
Dexie solves three main issues with the native IndexedDB API:
Dexie provides a neat database API with a well thought-through API design, robust error handling, extendability, change tracking awareness and extended KeyRange support (case insensitive search, set matches and OR operations).
<!doctype html>
<html>
<head>
<script src="https://unpkg.com/dexie@latest/dist/dexie.js"></script>
<script>
//
// Declare Database
//
var db = new Dexie("FriendDatabase");
db.version(1).stores({
friends: "++id,name,age"
});
//
// Manipulate and Query Database
//
db.friends.add({name: "Josephine", age: 21}).then(function() {
return db.friends.where("age").below(25).toArray();
}).then(function (youngFriends) {
alert ("My young friends: " + JSON.stringify(youngFriends));
}).catch(function (e) {
alert ("Error: " + (e.stack || e));
});
</script>
</head>
</html>
Yes, it's that simple.
Dexie has a kick-ass performance. It's bulk methods take advantage of a not well known feature in indexedDB that makes it possible to store stuff without listening to every onsuccess event. This speeds up the performance to a maximum.
above(key): Collection;
aboveOrEqual(key): Collection;
add(item, key?): Promise;
and(filter: (x) => boolean): Collection;
anyOf(keys[]): Collection;
anyOfIgnoreCase(keys: string[]): Collection;
below(key): Collection;
belowOrEqual(key): Collection;
between(lower, upper, includeLower?, includeUpper?): Collection;
bulkAdd(items: Array): Promise;
bulkDelete(keys: Array): Promise;
bulkPut(items: Array): Promise;
clear(): Promise;
count(): Promise;
delete(key): Promise;
distinct(): Collection;
each(callback: (obj) => any): Promise;
eachKey(callback: (key) => any): Promise;
eachPrimaryKey(callback: (key) => any): Promise;
eachUniqueKey(callback: (key) => any): Promise;
equals(key): Collection;
equalsIgnoreCase(key): Collection;
filter(fn: (obj) => boolean): Collection;
first(): Promise;
get(key): Promise;
inAnyRange(ranges): Collection;
keys(): Promise;
last(): Promise;
limit(n: number): Collection;
modify(changeCallback: (obj: T, ctx:{value: T}) => void): Promise;
modify(changes: { [keyPath: string]: any } ): Promise;
noneOf(keys: Array): Collection;
notEqual(key): Collection;
offset(n: number): Collection;
or(indexOrPrimayKey: string): WhereClause;
orderBy(index: string): Collection;
primaryKeys(): Promise;
put(item: T, key?: Key): Promise;
reverse(): Collection;
sortBy(keyPath: string): Promise;
startsWith(key: string): Collection;
startsWithAnyOf(prefixes: string[]): Collection;
startsWithAnyOfIgnoreCase(prefixes: string[]): Collection;
startsWithIgnoreCase(key: string): Collection;
toArray(): Promise;
toCollection(): Collection;
uniqueKeys(): Promise;
until(filter: (value) => boolean, includeStopEntry?: boolean): Collection;
update(key: Key, changes: { [keyPath: string]: any }): Promise;
This is a mix of methods from WhereClause, Table and Collection. Dive into the API reference to see the details.
This sample shows how to use Dexie with ES6 compliant environments and npm module resolution. With ES6, the yield keyword can be used instead of calling .then() on every database operation. The yield keyword and generator functions are already supported today (March 2016) in Chrome, Firefox, Edge and Opera without a transpiler (though this example also uses import statements which still needs transpilation). Dive into this? Read SIMPLIFY WITH YIELD!
import Dexie from 'dexie';
//
// Declare Database
//
let db = new Dexie("FriendDatabase");
db.version(1).stores({ friends: "++id,name,age" });
//
// Have Fun
//
db.transaction('rw', db.friends, function*() {
// Make sure we have something in DB:
if ((yield db.friends.where('name').equals('Josephine').count()) === 0) {
let id = yield db.friends.add({name: "Josephine", age: 21});
alert (`Addded friend with id ${id}`);
}
// Query:
let youngFriends = yield db.friends.where("age").below(25).toArray();
// Show result:
alert ("My young friends: " + JSON.stringify(youngFriends));
}).catch(e => {
alert(e.stack || e);
});
NOTE: db.transaction() will treat generator functions (function * ) so that it is possible to use yield for consuming promises. Yield can be used outside transactions as well.
import Dexie from 'dexie';
//
// Declare Database
//
var db = new Dexie("FriendDatabase");
db.version(1).stores({ friends: "++id,name,age" });
db.transaction('rw', db.friends, async() => {
// Make sure we have something in DB:
if ((await db.friends.where('name').equals('Josephine').count()) === 0) {
let id = await db.friends.add({name: "Josephine", age: 21});
alert (`Addded friend with id ${id}`);
}
// Query:
let youngFriends = await db.friends.where("age").below(25).toArray();
// Show result:
alert ("My young friends: " + JSON.stringify(youngFriends));
}).catch(e => {
alert(e.stack || e);
});
This sample requires using Dexie v2, npm install dexie@^2.0.0-beta
import Dexie from 'dexie';
interface IFriend {
id?: number;
name?: string;
age?: number;
}
//
// Declare Database
//
class FriendDatabase extends Dexie {
friends: Dexie.Table<IFriend,number>;
constructor() {
super("FriendDatabase");
this.version(1).stores({
friends: "++id,name,age"
});
}
}
var db = new FriendDatabase();
db.transaction('rw', db.friends, async() => {
// Make sure we have something in DB:
if ((await db.friends.where('name').equals('Josephine').count()) === 0) {
let id = await db.friends.add({name: "Josephine", age: 21});
alert (`Addded friend with id ${id}`);
}
// Query:
let youngFriends = await db.friends.where("age").below(25).toArray();
// Show result:
alert ("My young friends: " + JSON.stringify(youngFriends));
}).catch(e => {
alert(e.stack || e);
});
https://github.com/dfahlander/Dexie.js/wiki/Samples
https://github.com/dfahlander/Dexie.js/tree/master/samples
https://github.com/dfahlander/Dexie.js/wiki/Questions-and-Answers
npm install dexie@^2.0.0-beta
For those who don't like package managers, here's the download links:
https://unpkg.com/dexie@^2.0.0-beta/dist/dexie.js
https://unpkg.com/dexie@^2.0.0-beta/dist/dexie.js.map
https://unpkg.com/dexie@^2.0.0-beta/dist/dexie.d.ts
Here is a little cheat-sheet for how to symlink your app's node_modules/dexie to a place where you can edit the source, version control your changes and create pull requests back to Dexie. Assuming you've already ran npm install dexie --save for the app your are developing.
Fork Dexie.js from the web gui on github
Clone your fork locally by launching a shell/command window and cd to a neutral place (like ~repos/, c:\repos or whatever)
Run the following commands:
git clone https://github.com/YOUR-USERNAME/Dexie.js.git dexie
cd dexie
npm install
npm run build
npm link
cd to your app directory and write:
npm link dexie
Your app's node_modules/dexie/ is now sym-linked to the Dexie.js clone on your hard drive so any change you do there will propagate to your app. Build dexie.js using npm run build or npm run watch. The latter will react on any source file change and rebuild the dist files.
That's it. Now you're up and running to test and commit changes to files under dexie/src/* or dexie/test/* and the changes will instantly affect the app you are developing.
Pull requests are more than welcome. Some advices are:
test/tests-misc.js. We use qunit. Just look at existing tests in tests-misc.js to see how they should be written. Tests are transpiled in the build script so you can use ES6 if you like.npm install
npm run build
npm test
npm run watch
FAQs
A Minimalistic Wrapper for IndexedDB
We found that dexie demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 2 open source maintainers collaborating on the project.
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