refactor: Use a database type.

docs/DATABASES.md

@@ -205,7 +205,7 @@ db2.events.on('update', async (entry) => {
 
 To learn more, check out [OrbitDB's sychronization protocol](https://orbitdb.org/api/module-Sync.html) and the [OrbitDB replication documentation](./REPLICATION.md).
 
-## Building a custom database
+## Custom databases
 
 OrbitDB can be extended to use custom data models and database types. To implement a custom database, ensure the Database object is extended and that the OrbitDB database interface is implement. The database will also require a unique type.
 
@@ -260,3 +260,15 @@ export default CustomDB
 ```
 
 [Documents](../src/db/documents.js), [Events](../src/db/events.js) and [KeyValue](../src/db/keyvalue.js) provide good examples of how a database is implemented in OrbitDB and how to add the logic for returning records from the database (the state of the database).
+
+To use a custom database, add it to the list of supported database types:
+
+```js
+import { createOrbitDB, useDatabaseType } from '@orbitdb/core'
+import { CustomDB } from './custom-db.js'
+
+useDatabaseType(CustomDB)
+const orbitdb = await createOrbitDB()
+await orbitdb.open('my-custom-db', { type: 'customdb' })
+```
+

src/databases/index.js

@@ -20,27 +20,23 @@ const databaseTypes = {}
 /**
  * Add a new database type.
  * @example
- * import { addDatabaseType } from 'orbitdb'
+ * import { useDatabaseType } from 'orbitdb'
  * const CustomDBTypeModule = async (params) => {
  *   const database = await Database(...params)
  *   ...
  * }
- * addDatabaseType(CustomDBTypeModule)
- * @function addDatabaseType
+ * useDatabaseType(CustomDBTypeModule)
+ * @function useDatabaseType
  * @param {module:Databases} database A Database-compatible module.
  * @throws Database type does not contain required field \'type\'.
  * @throws Database type '${store.type}' already added.
  * @memberof module:Databases
  */
-const addDatabaseType = (database) => {
+const useDatabaseType = (database) => {
   if (!database.type) {
     throw new Error('Database type does not contain required field \'type\'.')
   }
 
-  if (databaseTypes[database.type]) {
-    throw new Error(`Database type '${database.type}' already added.`)
-  }
-
   databaseTypes[database.type] = database
 }
 
@@ -56,9 +52,8 @@ const getDatabaseType = (type) => {
   return databaseTypes[type]
 }
 
-addDatabaseType(Events)
-addDatabaseType(Documents)
-addDatabaseType(KeyValue)
-addDatabaseType(KeyValueIndexed)
+useDatabaseType(Events)
+useDatabaseType(Documents)
+useDatabaseType(KeyValue)
 
-export { addDatabaseType, getDatabaseType, Documents, Events, KeyValue, KeyValueIndexed }
+export { useDatabaseType, getDatabaseType, Documents, Events, KeyValue, KeyValueIndexed }

src/databases/keyvalue-indexed.js

@@ -21,7 +21,6 @@ import KeyValue from './keyvalue.js'
 import LevelStorage from '../storage/level.js'
 import pathJoin from '../utils/path-join.js'
 
-const type = 'keyvalueindexed'
 const valueEncoding = 'json'
 
 /**
@@ -120,6 +119,4 @@ const KeyValueIndexed = ({ storage } = {}) => async ({ ipfs, identity, address,
   }
 }
 
-KeyValueIndexed.type = type
-
 export default KeyValueIndexed

src/index.js

@@ -7,7 +7,7 @@ export {
   Events,
   KeyValue,
   KeyValueIndexed,
-  addDatabaseType
+  useDatabaseType
 } from './databases/index.js'
 
 export {

test/orbitdb-custom-database-types.test.js

@@ -2,7 +2,7 @@ import { strictEqual, deepStrictEqual, notStrictEqual } from 'assert'
 import rmrf from 'rimraf'
 import * as IPFS from 'ipfs-core'
 import { getDatabaseType } from '../src/databases/index.js'
-import { createOrbitDB, addDatabaseType, Database } from '../src/index.js'
+import { createOrbitDB, useDatabaseType, Database } from '../src/index.js'
 import config from './config.js'
 
 const type = 'custom!'
@@ -57,7 +57,7 @@ describe('Add a custom database type', function () {
 
   describe('Custom database type', function () {
     before(() => {
-      addDatabaseType(CustomStore)
+      useDatabaseType(CustomStore)
     })
 
     it('create a database with the custom database type', async () => {
@@ -67,18 +67,6 @@ describe('Add a custom database type', function () {
       strictEqual(db.name, name)
     })
 
-    it('throws and error if custom database type already exists', async () => {
-      let err
-      try {
-        addDatabaseType(CustomStore)
-        throw new Error('This should not run.')
-      } catch (e) {
-        err = e.toString()
-      }
-
-      strictEqual(err, 'Error: Database type \'custom!\' already added.')
-    })
-
     it('returns custom database type after adding it', async () => {
       deepStrictEqual(getDatabaseType(type), CustomStore)
     })