$mol_db

Static typed facade for IndexedDB with simple API.

Teaser

1type User = {
2	name: string
3	admin: boolean
4}
5
6// Static typed schema
7type DB = {
8	User: {
9		Key: [ string ]
10		Doc: User
11		Indexes: {
12			Name: [ string ]
13		}
14	}
15}
16
17// Automatic migrations
18const db = await $mol_db< DB >( '$my_app',
19	mig => mig.store_make( 'User' ),
20	mig => {
21		const { User } = mig.stores
22		User.index_make( 'Name', [ 'name' ] )
23	},
24)
25
26// Writing transaction
27const { User } = db.change( 'User' ).stores
28await User.put({ name: 'Jin', admin: true })
29
30// Reading transaction
31const { Name } = db.read( 'User' ).User.indexes
32const jins = await Name.select([ 'Jin' ])

IndexedDB Structure

• Database contains named Stores
• • Store contains Documents by primary keys and named Indexes
• • • Document contains any data
• • • Index points to Documents

DB life Cycle

DB Schema Example

1type ACME = {
2	Users: {
3		Key: number
4		Doc: {
5			name: {
6				first: string
7				last: string
8			}
9			age: number
10		}
11		Indexes: {
12			names: [ string, string ]
13			ages: [ number ]
14		}
15	}
16	Articles: {
17		Key: string
18		Doc: {
19			title: string
20			content: string
21		}
22		Indexes: {
23			full: [ string, string ]
24		}
25	}
26}

Open DB without Migrations

1const db = await $$.$mol_db< ACME >( 'ACME' )

Open DB with automatic migrations

1const db = await $$.$mol_db< ACME >( 'ACME',
2	mig => mig.store_make( 'Users' ),
3	mig => mig.stores.Users.index_make( 'ages', [ 'age' ] ),
4	mig => mig.stores.Users.index_make( 'names', [ 'name.first', 'name.last' ], true ),
5	mig => mig.store_make( 'Articles' ),
6	mig => mig.stores.Articles.index_make( 'full', [ 'title', 'content' ] ),
7	// mig => mig.stores.Articles.index_drop( 'full' ),
8	// mig => mig.store_drop( 'Articles' ),
9)

There is 5 migrations. And DB version is 6. After uncommenting last 2 rows, it applies 2 additional migrations and DB version will be 8.

Close DB Connection

1db.destructor()

Delete DB

1db.kill()

Transaction Life Cycle

Read Only Transactions

1const { Users, Articles } = db.read( 'Users', 'Articles' )

Read/Write Trasactions

1const trans = db.change( 'Users', 'Articles' )
2const { Users, Articles } = trans.stores
3
4// ...
5
6trans.abort()
7// or
8await trans.commit()

Uncommitted transaction without errors will be committed automatically. Any modification error aborts transaction.

Documents Life Cycle

By Primary key

Insert with Auto Incremental Primary Key

1const key = await Users.put({
2	first: 'Jin',
3	last: 'Nin',
4	age: 36,
5})

Put/Overwrite by Primary Key

1await Users.put( {
2	first: 'Jin',
3	last: 'Nin',
4	age: 37,
5}, 1 )

Get One By Primary Key

1const user = await Users.get( 1 )

Select 10 By Primary Keys

1const users = await Users.get( $mol_dom_context.IDBKeyRange.bound( 10, 50 ), 10 )

Count By Primary Keys

1const count = await Users.count( $mol_dom_context.IDBKeyRange.bound( 10, 50 ) )

By Index

1const { names, ages } = users.indexes

Get One By Index

1const user = await names.get([ 'Jin', 'Nin' ])

Select 10 By Index

1const users = await ages.get( [ 18 ], 10 )

Count By Primary Keys

1const count = await Users.count([ 18 ])

Usage from NPM

npm install mol_db

1import { $mol_db } from 'mol_db'