commit 8c24feee9a4cf2bf1bbf0cf44811187060e7f1f2
Author: Timothy Farrell <tim@thecookiejar.me>
Date:   Wed Jul 4 08:22:23 2018 -0500

    PouchORM becomes PouchType
    
    API changed and full test coverage.

diff --git a/packages/pouchtype/README.md b/packages/pouchtype/README.md
new file mode 100644
index 0000000..d9bc899
--- /dev/null
+++ b/packages/pouchtype/README.md
@@ -0,0 +1,137 @@
+# PouchType
+
+An type-based abstraction layer over PouchDB inspired by [Hood.ie](https://hood.ie/) and
+[Django](https://djangoproject.com)
+
+## Extending the TypeHandler class
+
+PouchType works by extending the _TypeHandler_ class with methods to define how a document type
+should be handled. The resulting class is instantiated with a PouchDB instance and used to interact
+with documents of that type.
+
+All subclasses of _TypeHandler_ must override the `getUniqueID` method. This method should return a
+unique string for documents of this type. (NOTE: The document id will be prefixed with the
+type_string as well to avoid collisions across types.)
+
+```js
+import { PouchDB } from 'pouchdb';
+import { TypeHandler } from 'PouchType';
+
+const PDB = PouchDB.plugin(find); // PouchType requires the find plugin.
+
+class ContactHandler extends TypeHandler {
+	getUniqueID(doc) {
+		return doc.email;
+	}
+
+	validate(doc) {
+		super.validate(doc);
+
+		if (typeof doc.email != 'string') {
+			throw new Error('email property is required');
+		} else if (doc.email.length <= 2) {
+			throw new Error('email must be longer than 2 characters');
+		}
+	}
+}
+```
+
+## TypeHandler management methods
+
+### getUniqueID(doc)
+
+_This method must be overridden in subclasses._
+
+Return a unique string that will be used to populate `doc._id` if it isn't already populated.
+
+### hash(doc)
+
+Returns a hash string of the current document for comparison. By default this is
+"`doc._id`:`doc._rev`" and will work as long as the hash is only taken after any changes are saved.
+You may wish to override this to provide content-specific hashing.
+
+### index(name, fields)
+
+Create a index to be used in a `filter` selector and sort options. Specify the `name` of the index
+and the `fields` as an array of strings of the document properties to include in the index.
+
+### isType(doc)
+
+Check if the passed `doc` belongs to this handler.
+
+### validate(doc)
+
+Check if the passed `doc` has valid data before it is written. Invalidation happens by raising an
+exception. For more fine-grained validation, refer to the
+[pouchdb-validation](https://github.com/pouchdb/pouchdb-validation) plugin or the
+[validate_doc_update](http://guide.couchdb.org/draft/validation.html) function.
+
+## TypeHandler query methods
+
+### get(id)
+
+Return the document referenced by `id` or `null` if the document does not exist.
+
+### getOrCreate(doc, defaults={})
+
+If the passed document doesn't have a `_id` property, populate it. Try to lookup a document with the
+`id`. If it exists, update it with the properties in `doc`. If it does not exist, add the properties
+in `defaults` to `props` and save the new document.
+
+### filter(selector, options={})
+
+Return an array of documents that match the criteria in `selector`. `options.index` can contain the
+`name` passed to `index()` if needed. All other option properties are passed through to the
+[PouchDB.find()](https://pouchdb.com/api.html#query_index)
+
+### watch(selector, options={})
+
+The parameters for `watch()` are identical to `filter()` but `watch()` returns a
+[computed](../frptools/README.md#computed) instance that will call subscribers whenever any data
+matching the selector changes.
+
+## TypeHandler change methods
+
+### remove(docOrId)
+
+`remove` accepts a document or an id string.
+
+Flag this document as `doc._deleted == true`. This will cause it to not show up in `get`, `filter`
+or `watch` results. (_Note_: documents are left in the database in this state to allow for deletion
+to be synced to other nodes. To truly remove documents,
+[compact your database](https://pouchdb.com/api.html#compaction).)
+
+### save(doc)
+
+If the document does not have properties `_id` or `type`, populate them appropriately. Run
+`TypeHandler.validate` on the document. If validate doesn't throw any errors, then save the document
+to the database. It's `_rev` property will be updated to reflect the revision in the database.
+
+### update(doc, props)
+
+Deeply assign `props` to the passed `doc` object and `save()` it.
+
+### addAttachment(doc, key, blob)
+
+Attach the passed `blob` to the document referenced with the `key` string.
+
+### removeAttachment(doc, key)
+
+Remove a previously attached blob at `key`.
+
+### getAttachment(doc, key)
+
+Return a previously attached blob at `key` or `null` if none exists.
+
+## Using Types
+
+```js
+const db = PDB('type_example');
+
+export const Contact = new ContactHandler(db, 'contact');
+
+const doc = await Contact.getOrCreate({
+    name: "John Doe",
+    email: "jd@example.com"
+});
+```
diff --git a/packages/pouchtype/package.json b/packages/pouchtype/package.json
new file mode 100644
index 0000000..05ace4b
--- /dev/null
+++ b/packages/pouchtype/package.json
@@ -0,0 +1,16 @@
+{
+	"name": "pouchtype",
+	"version": "1.0.0",
+	"description": "Document Management Layer for PouchDB",
+	"main": "src/index.js",
+	"files": ["dist", "lib", "src"],
+	"scripts": {
+		"test": "node ../../bin/runTests.js ./"
+	},
+	"author": "Timothy Farrell <tim@thecookiejar.me> (https://github.com/explorigin)",
+	"license": "Apache-2.0",
+	"dependencies": {
+		"frptools": "~3.2.1",
+		"pouchdb": "~7.0.0"
+	}
+}
diff --git a/packages/pouchtype/spec/livearray.spec.js b/packages/pouchtype/spec/livearray.spec.js
new file mode 100644
index 0000000..139cdd4
--- /dev/null
+++ b/packages/pouchtype/spec/livearray.spec.js
@@ -0,0 +1,79 @@
+import { LiveArray } from '../src/livearray.js';
+import { pouchDocArrayHash } from '../src/utils.js';
+
+describe('A LiveArray', () => {
+	let fakePouch;
+	const selector = {};
+	const opts = {};
+
+	beforeEach(() => {
+		fakePouch = {
+			find: () => {},
+			changes: () => fakePouch,
+			on: () => fakePouch
+		};
+	});
+
+	it('returns a computed (subscribable).', async () => {
+		const la = await LiveArray(fakePouch, selector, opts);
+
+		expect(typeof la).toEqual('function');
+		expect(typeof la.subscribe).toEqual('function');
+
+		expect(JSON.stringify(la())).toEqual('[]');
+	});
+
+	it('fires when data changes.', async () => {
+		let state = 0;
+		const changes = {
+			234: { id: 234, deleted: false, doc: { _id: 234 } },
+			34: { id: 34, deleted: true, doc: { _id: 34 } },
+			4564565: { id: 4564565, deleted: false, doc: { _id: 4564565 } }
+		};
+		const changeKeys = Object.keys(changes);
+		let sub = null;
+
+		const db = {
+			changes: options => {
+				expect(state).toEqual(1);
+				expect(options.live).toEqual(true);
+				expect(options.since).toEqual('now');
+				expect(options.selector).toBe(selector);
+				return db;
+			},
+			on: (eventName, callback) => {
+				if (eventName == 'change') {
+					sub = callback;
+				}
+				expect(['change', 'error'].indexOf(eventName) !== -1).toBeTruthy();
+				return db;
+			},
+			cancel: () => (sub = null),
+			find: async selector => {
+				const doc = changes[parseInt(changeKeys[state - 1])];
+				state += 1;
+				if (doc === undefined || doc.deleted) {
+					return Promise.resolve({ docs: [] });
+				}
+				return Promise.resolve({ docs: [doc.doc] });
+			}
+		};
+
+		const la = await LiveArray(db, selector, opts);
+		state = 1;
+
+		let innerState = 0;
+
+		la.subscribe(data => {
+			if (data.length) {
+				expect(data[0]._id).toEqual(parseInt(changeKeys[innerState]));
+			}
+			innerState += 1;
+		});
+
+		changeKeys.forEach(id => {
+			const doc = changes[parseInt(id)];
+			sub(doc);
+		});
+	});
+});
diff --git a/packages/pouchtype/spec/typehandler.spec.js b/packages/pouchtype/spec/typehandler.spec.js
new file mode 100644
index 0000000..b7324c2
--- /dev/null
+++ b/packages/pouchtype/spec/typehandler.spec.js
@@ -0,0 +1,360 @@
+import { TypeHandler } from '../src/index.js';
+
+const PDB = PouchDB.plugin(find);
+
+class ContactHandler extends TypeHandler {
+	getUniqueID(doc) {
+		return doc.email;
+	}
+
+	validate(doc) {
+		if (typeof doc.email != 'string') {
+			throw new Error('email property is required');
+		} else if (doc.email.length <= 2) {
+			throw new Error('email must be more than 2 characters');
+		}
+	}
+}
+
+class LocationHandler extends TypeHandler {
+	getUniqueID(doc) {
+		return doc.latlon;
+	}
+}
+
+const notDesignDocs = d => !d.id.startsWith('_design');
+
+function compareDataToDoc(dataObj, doc) {
+	Object.keys(dataObj).forEach(k => {
+		expect(doc[k]).toEqual(dataObj[k]);
+	});
+}
+
+describe('PouchType Handler', () => {
+	const db = new PDB('pouchtype-test', { adapter: 'memory' });
+	const Contact = new ContactHandler(db, 'contact');
+	const Location = new LocationHandler(db, 'location');
+
+	Contact.index('lastIndex', ['last']);
+
+	const dataset = [
+		{
+			first: 'Jane',
+			last: 'Doe',
+			email: 'jd@example.com',
+			type: 'contact',
+			_id: 'contact_jd@example.com'
+		},
+		{
+			first: 'Bob',
+			last: 'Smith',
+			email: 'bs@example.com',
+			type: 'contact',
+			_id: 'contact_bs@example.com'
+		},
+		{
+			description: 'Home',
+			latlon: '12345',
+			type: 'location',
+			_id: 'location_12345'
+		},
+		{
+			first: 'Joe',
+			last: 'Smithers',
+			email: 'js@example.com',
+			type: 'contact',
+			_id: 'contact_js@example.com'
+		}
+	];
+
+	async function flushDb() {
+		const res = await db.allDocs();
+		await Promise.all(res.rows.filter(notDesignDocs).map(d => db.remove(d.id, d.value.rev))).catch(
+			() => {}
+		);
+		await db.compact();
+	}
+
+	afterEach(flushDb);
+
+	it('.getOrCreate() gets existing records.', async () => {
+		const doc = {
+			first: 'Jane',
+			last: 'Doe',
+			email: 'jd@example.com'
+		};
+		await db.bulkDocs(dataset);
+		const existing = await db.get(dataset[0]._id);
+		const instance = await Contact.getOrCreate(doc);
+		expect(instance._id).toEqual(existing._id);
+		expect(instance._rev).toEqual(existing._rev);
+	});
+
+	it('.getOrCreate() saves non-existing records and populates _id and _rev.', async () => {
+		const doc = {
+			first: 'Jill',
+			last: 'Doener',
+			email: 'jd2@example.com'
+		};
+		const expectedId = `${Contact.type}_${doc.email}`;
+		try {
+			await db.get(expectedId);
+			fail('db.get() should throw when passed an id of a removed document.');
+			return;
+		} catch (e) {
+			expect(e.status).toBe(404);
+		}
+
+		const instance = await Contact.getOrCreate(doc);
+		expect(instance._id).toEqual(expectedId);
+		expect(instance._rev).toBeTruthy();
+		compareDataToDoc(doc, instance);
+		const savedDoc = await db.get(expectedId);
+		expect(savedDoc._id).toEqual(expectedId);
+		expect(savedDoc._rev).toBeTruthy();
+		compareDataToDoc(doc, savedDoc);
+	});
+
+	it('.get() returns a document when it exists.', async () => {
+		await db.bulkDocs(dataset);
+		const instance = await Contact.get(dataset[1]._id);
+		compareDataToDoc(dataset[1], instance);
+	});
+
+	it(".get() returns null when it doesn't exist or has been removed.", async () => {
+		await db.bulkDocs(dataset);
+		const empty = await Contact.get('does_not_exist');
+		expect(empty).toBeNull();
+		const doc = await db.get(dataset[1]._id);
+		doc._deleted = true;
+		await db.put(doc);
+		const empty2 = await Contact.get('does_not_exist');
+		expect(empty).toBeNull();
+	});
+
+	it('.get() only returns records for its type.', async () => {
+		await db.bulkDocs(dataset);
+		const instance = await Contact.get(dataset.filter(d => d.type !== Contact.type)[0]._id);
+		expect(instance).toBeNull();
+	});
+
+	it('.filter() returns an array of matching instances.', async () => {
+		await db.bulkDocs(dataset);
+		const res = await Contact.filter({ last: { $regex: /^Smith.*/ } });
+		expect(res.length).toBe(2);
+	});
+
+	it('.filter() only returns records for its type.', async () => {
+		await db.bulkDocs(dataset);
+		const res = await Contact.filter({});
+		expect(res.length).toBe(3);
+		res.forEach(c => expect(c.type).toBe(Contact.type));
+	});
+
+	it('.isType(instance) identifies instances of the type.', async () => {
+		const instance = await Contact.getOrCreate({
+			first: 'Bob',
+			last: 'Smith',
+			email: 'bs@example.com'
+		});
+
+		expect(Contact.isType(instance)).toBe(true);
+	});
+
+	it('.isType(doc) detects documents of the type.', async () => {
+		const data = await Contact.getOrCreate({
+			first: 'Bob',
+			last: 'Smith',
+			email: 'bs@example.com'
+		});
+		const doc = await db.get(data._id);
+
+		expect(Contact.isType(doc)).toBe(true);
+	});
+
+	it('.remove() sets the ._deleted property and documents are no longer gettable.', async () => {
+		const id = dataset[1]._id;
+		await db.bulkDocs(dataset);
+		const doc = await Contact.get(id);
+		await Contact.remove(doc);
+		expect(doc._deleted).toBe(true);
+		try {
+			await db.get(id);
+			fail('db.get() should throw when passed an id of a removed document.');
+			return;
+		} catch (e) {
+			expect(e.status).toBe(404);
+		}
+		const doc2 = await Contact.get(id);
+		expect(doc2).toBeNull();
+	});
+
+	it('.save() populates ._id and .type  properties and writes to the db.', async () => {
+		const doc = {
+			first: 'Bob',
+			last: 'Smith',
+			email: 'bs@example.com'
+		};
+		await Contact.save(doc);
+		const d = await db.get(doc._id);
+		expect(Contact.isType(d)).toBe(true);
+		expect(d._id).toBeTruthy();
+		expect(d.type).toEqual(Contact.type);
+		compareDataToDoc(doc, d);
+	});
+
+	it('.validate() can interrupt save() by throwing an exception.', async () => {
+		const doc = {
+			first: 'Bob',
+			last: 'Smith',
+			email: 'bs'
+		};
+		try {
+			await Contact.save(doc);
+		} catch (e) {
+			expect(e.message).toBe('email must be more than 2 characters');
+			return;
+		}
+		fail('TypeHandler.save() should call validate on save()');
+	});
+
+	it('.update() will deeply apply object properties to a document.', async () => {
+		const data = {
+			first: 'Bob',
+			last: 'Smitherines',
+			email: 'bsmitherines@example.com',
+			addresses: {
+				home: '123 Privet Drive'
+			}
+		};
+		const doc = await Contact.save(data);
+		await Contact.update(doc, { addresses: { home: '221B Baker Street' } });
+		const doc2 = await Contact.get(doc._id);
+		expect(doc2.addresses.home).toEqual(doc.addresses.home);
+	});
+
+	it('.update() only updates the database when the underlying document changes and save is not precluded.', async () => {
+		const data = {
+			first: 'Bob',
+			last: 'Smitherines',
+			email: 'bsmitherines@example.com'
+		};
+		const doc = await Contact.save(data);
+		spyOn(Contact, 'save');
+		await Contact.update(doc, { last: 'Shell', email: 'bshell@example.com' });
+		expect(Contact.save).toHaveBeenCalledTimes(1);
+		await Contact.update(doc, { last: 'Shell' });
+		expect(Contact.save).toHaveBeenCalledTimes(1);
+		await Contact.update(doc, { last: 'Tootsie' }, false);
+		expect(Contact.save).toHaveBeenCalledTimes(1);
+
+		// TODO: Potentially undesirable/non-intuitive behavior here.  Update calls save even though the data hasn't truly changed from the last saved state.
+		await Contact.update(doc, { last: 'Shell' });
+		expect(Contact.save).toHaveBeenCalledTimes(2);
+	});
+
+	it('.watch() returns a subscribable LiveArray of matching instances.', done => {
+		let expectedLength = 0;
+		let checkCount = 0;
+		let sub;
+		let livedata;
+
+		function poll(fn, val) {
+			return new Promise(resolve => {
+				const wrap = () => {
+					if (fn()) {
+						resolve(val);
+					} else {
+						setTimeout(wrap, 5);
+					}
+				};
+				wrap();
+			});
+		}
+
+		return Contact.watch({ watchTest: { $eq: true } })
+			.then(_ld => {
+				livedata = _ld;
+				sub = livedata.subscribe(data => {
+					checkCount += 1;
+					expect(data.length).toBe(expectedLength);
+				});
+				return db.bulkDocs(dataset);
+			})
+			.then(_ =>
+				poll(() => {
+					return livedata().length === 0;
+				})
+			)
+			.then(_ => {
+				expectedLength = 1;
+				return db.put({
+					first: 'Bill',
+					last: 'Smitherts',
+					email: 'bsmithers@example.com',
+					_id: 'contact_bsmithers@example.com',
+					type: 'contact',
+					watchTest: true
+				});
+			})
+			.then(_ =>
+				poll(() => {
+					return livedata().length === 1;
+				})
+			)
+			.then(_ => {
+				return db.put({
+					first: 'Bart',
+					last: 'Smitty',
+					email: 'bsmitty@example.com',
+					type: 'contact',
+					_id: 'contact_bsmitty@example.com'
+				});
+			})
+			.then(res => {
+				return poll(() => {
+					return livedata().length === 1;
+				}, res);
+			})
+			.then(res => {
+				expectedLength = 2;
+				db.put({
+					first: 'Bart',
+					last: 'Smitty',
+					email: 'bsmitty@example.com',
+					type: 'contact',
+					_id: 'contact_bsmitty@example.com',
+					_rev: res.rev,
+					watchTest: true
+				});
+				return poll(() => {
+					return livedata().length === 2;
+				});
+			})
+			.then(_ => {
+				expect(livedata().length).toBe(expectedLength);
+			})
+			.then(done);
+	});
+
+	it('.index() creates an index for non-id sorting.', async () => {
+		await db.bulkDocs(dataset);
+		try {
+			const res = await Contact.filter(
+				{
+					last: { $gte: '' }
+				},
+				{
+					sort: ['last'],
+					index: 'lastIndex'
+				}
+			);
+			expect(res.length).toEqual(3);
+			expect(res[0].last).toEqual('Doe');
+			expect(res[1].last).toEqual('Smith');
+			expect(res[2].last).toEqual('Smithers');
+		} catch (e) {
+			fail(e);
+		}
+	});
+});
diff --git a/packages/pouchtype/spec/watcher.spec.js b/packages/pouchtype/spec/watcher.spec.js
new file mode 100644
index 0000000..fc38e03
--- /dev/null
+++ b/packages/pouchtype/spec/watcher.spec.js
@@ -0,0 +1,148 @@
+import { Watcher } from '../src/watcher.js';
+
+describe('A watcher', () => {
+	const selector = {};
+	const opts = {};
+
+	it('initially does nothing.', () => {
+		const db = {
+			changes: () => fail('Watcher should not call changes until the first subscription.')
+		};
+
+		const w = Watcher(db, selector, opts);
+		expect().nothing();
+	});
+
+	it('calls PouchDB.change API on the first subscription.', () => {
+		let state = 0;
+		const db = {
+			changes: options => {
+				expect(state).toEqual(1);
+				expect(options.live).toEqual(true);
+				expect(options.since).toEqual('now');
+				expect(options.selector).toBe(selector);
+				return db;
+			},
+			on: (eventName, callback) => {
+				expect(['change', 'error'].indexOf(eventName) !== -1).toBeTruthy();
+				return db;
+			},
+			cancel: () => {}
+		};
+
+		const w = Watcher(db, selector, opts);
+		state = 1;
+		w(() => fail('Subscription callback should not be called until data changes.'));
+	});
+
+	it('cancels change subscription when the last subscriber unsubscribes', () => {
+		let state = 0;
+		const db = {
+			changes: options => {
+				expect(state).toEqual(1);
+				expect(options.live).toEqual(true);
+				expect(options.since).toEqual('now');
+				expect(options.selector).toBe(selector);
+				return db;
+			},
+			on: (eventName, callback) => {
+				expect(['change', 'error'].indexOf(eventName) !== -1).toBeTruthy();
+				return db;
+			},
+			cancel: () => {
+				expect(state).toEqual(2);
+				state = 3;
+			}
+		};
+
+		const w = Watcher(db, selector, opts);
+		state = 1;
+		const unsub = w(() => fail('Subscription callback should not be called until data changes.'));
+		state = 2;
+		unsub();
+		expect(state).toEqual(3);
+	});
+
+	it('passes change events to subscribers.', () => {
+		let state = 0;
+		const changes = {
+			234: { id: 234, deleted: false, doc: { _id: 234 } },
+			34: { id: 34, deleted: true, doc: { _id: 34 } },
+			4564565: { id: 4564565, deleted: false, doc: { _id: 4564565 } }
+		};
+		let sub = null;
+		const db = {
+			changes: options => {
+				expect(state).toEqual(1);
+				expect(options.live).toEqual(true);
+				expect(options.since).toEqual('now');
+				expect(options.selector).toBe(selector);
+				return db;
+			},
+			on: (eventName, callback) => {
+				if (eventName == 'change') {
+					sub = callback;
+				}
+				expect(['change', 'error'].indexOf(eventName) !== -1).toBeTruthy();
+				return db;
+			},
+			cancel: () => (sub = null)
+		};
+
+		const w = Watcher(db, selector, opts);
+		state = 1;
+		w((id, deleted, doc) => {
+			expect(changes.hasOwnProperty(id)).toBeTruthy();
+			expect(changes[id].doc).toBe(doc);
+			expect(changes[id].deleted).toEqual(deleted);
+		});
+
+		Object.values(changes).forEach(sub);
+	});
+
+	it('dumps subscribers when an error event happens.', () => {
+		let state = 0;
+		const changes = {
+			234: { id: 234, deleted: false, doc: { _id: 234 } },
+			34: { id: 34, deleted: true, doc: { _id: 34 } },
+			4564565: { id: 4564565, deleted: false, doc: { _id: 4564565 } }
+		};
+		let sub = null;
+		let errorSub = null;
+		const db = {
+			changes: options => {
+				expect(state).toEqual(1);
+				expect(options.live).toEqual(true);
+				expect(options.since).toEqual('now');
+				expect(options.selector).toBe(selector);
+				return db;
+			},
+			on: (eventName, callback) => {
+				if (eventName == 'change') {
+					sub = callback;
+				}
+				if (eventName == 'error') {
+					errorSub = callback;
+				}
+				expect(['change', 'error'].indexOf(eventName) !== -1).toBeTruthy();
+				return db;
+			},
+			cancel: () => {
+				sub = null;
+				errorSub = null;
+			}
+		};
+
+		const w = Watcher(db, selector, opts);
+		state = 1;
+		w(() => fail('Subscription callback should not be called until data changes.'));
+
+		const error = new Error('TestError');
+		try {
+			errorSub(error);
+		} catch (e) {
+			expect(e).toBe(error);
+		}
+		Object.values(changes).forEach(sub);
+	});
+});
diff --git a/packages/pouchtype/src/index.js b/packages/pouchtype/src/index.js
new file mode 100644
index 0000000..7eae1e1
--- /dev/null
+++ b/packages/pouchtype/src/index.js
@@ -0,0 +1,2 @@
+import { isObject, deepAssign, pouchDocHash, pouchDocArrayHash } from './utils.js';
+export { TypeHandler } from './type.js';
diff --git a/packages/pouchtype/src/livearray.js b/packages/pouchtype/src/livearray.js
new file mode 100644
index 0000000..fe4a5f7
--- /dev/null
+++ b/packages/pouchtype/src/livearray.js
@@ -0,0 +1,45 @@
+import { prop, computed, id } from '../node_modules/frptools/src/index.js';
+
+import { Watcher } from './watcher.js';
+import { pouchDocArrayHash } from './utils.js';
+
+// LiveArray is a subscribable property function that always returns the db results that match
+// the provided selector and calls subscribers when the results change.
+export async function LiveArray(db, selector, opts = {}) {
+	opts.include_docs = true;
+	const _watcher = Watcher(db, selector, opts);
+	let changeSub = null;
+
+	const paginator = opts.paginator;
+	const data = prop({ docs: [] });
+	const docs = computed(r => r.docs, [data], pouchDocArrayHash);
+
+	const cleanup = () => {
+		docs.unsubscribeAll();
+		if (changeSub) {
+			changeSub();
+			changeSub = null;
+		}
+		data({ docs: [] });
+	};
+
+	const refresh = async function refresh(...args) {
+		const queryOpts = { selector };
+		if (paginator) {
+			Object.assign(queryOpts, paginator.queryOptions());
+		}
+		data(await db.find(queryOpts));
+	};
+
+	docs.cleanup = cleanup;
+	docs.selector = selector;
+	docs.db = db;
+
+	await refresh();
+	changeSub = _watcher(refresh);
+	if (paginator) {
+		paginator.queryOptions.subscribe(refresh);
+	}
+
+	return docs;
+}
diff --git a/packages/pouchtype/src/type.js b/packages/pouchtype/src/type.js
new file mode 100644
index 0000000..472d024
--- /dev/null
+++ b/packages/pouchtype/src/type.js
@@ -0,0 +1,132 @@
+import { pouchDocHash, deepAssign } from './utils.js';
+import { LiveArray } from './livearray.js';
+
+export class TypeHandler {
+	constructor(db, typeKey) {
+		this.db = db;
+		this.type = typeKey;
+	}
+
+	getUniqueID(doc) {
+		return undefined; // To be overridden if you want deterministic IDs.
+	}
+
+	_makeID(doc) {
+		return `${this.type}_${this.getUniqueID(doc)}`;
+	}
+
+	isType(doc) {
+		return doc && doc.type === this.type;
+	}
+
+	hash(doc) {
+		return pouchDocHash(doc);
+	}
+
+	async validate(doc) {
+		if (!this.isType(doc)) {
+			throw TypeError(`Document "${doc.type}:${doc._id}" does not match type "${this.type}"`);
+		}
+	}
+
+	async remove(docOrId) {
+		const doc = typeof docOrId === 'string' ? await this.get(docOrId) : docOrId;
+		return await this.update(doc, { _deleted: true });
+	}
+
+	async save(doc) {
+		if (!doc.type) {
+			doc.type = this.type;
+		}
+		this.validate(doc);
+		if (!doc._id) {
+			doc._id = this._makeID(doc);
+		}
+		if (!doc.$$links) {
+			doc.$$links = {};
+		}
+
+		const { rev } = await this.db.put(doc);
+		doc._rev = rev;
+		return doc;
+	}
+
+	async addAttachment(doc, attName, dataBlob) {
+		const { rev } = await this.db.putAttachment(doc._id, attName, doc._rev, dataBlob, dataBlob.type);
+
+		doc._rev = rev;
+		return doc;
+	}
+
+	async getAttachment(doc, attName) {
+		return await this.db.getAttachment(doc._id, attName);
+	}
+
+	async removeAttachment(doc, attName) {
+		return await this.db.removeAttachment(doc._id, attName, doc._rev);
+	}
+
+	async update(doc, props, save = true) {
+		if (deepAssign(doc, props) && save) {
+			await this.save(doc);
+		}
+		return doc;
+	}
+
+	_filterOpts(selector, opts) {
+		selector.type = { $eq: this.type };
+		opts.selector = selector;
+		if (opts.index) {
+			opts.use_index = `${this.type}_${opts.index}`;
+			delete opts.index;
+		}
+		return opts;
+	}
+
+	async filter(selector, opts = {}) {
+		const res = await this.db.find(this._filterOpts(selector, opts));
+		return res.docs;
+	}
+
+	async watch(selector, opts = {}) {
+		opts.live = true;
+		this._filterOpts(selector, opts);
+		return await LiveArray(this.db, opts.selector, opts);
+	}
+
+	async get(id) {
+		try {
+			const doc = await this.db.get(id);
+			return this.isType(doc) ? doc : null;
+		} catch (e) {
+			if (e.status === 404) {
+				return null;
+			}
+			throw e;
+		}
+	}
+
+	async getOrCreate(props, defaults = {}) {
+		const doc = Object.assign({}, defaults, props);
+		if (!doc._id) {
+			doc._id = this._makeID(doc);
+		}
+		const existing_doc = doc._id && (await this.get(doc._id));
+
+		if (existing_doc) {
+			return this.update(existing_doc, props);
+		}
+
+		return await this.save(doc);
+	}
+
+	async index(name, fields) {
+		return this.db.createIndex({
+			index: {
+				ddoc: `${this.type}_${name}`,
+				fields: fields,
+				name
+			}
+		});
+	}
+}
diff --git a/packages/pouchtype/src/utils.js b/packages/pouchtype/src/utils.js
new file mode 100644
index 0000000..a141840
--- /dev/null
+++ b/packages/pouchtype/src/utils.js
@@ -0,0 +1,30 @@
+export function deepAssign(to, ...rest) {
+	let updated = false;
+	for (let src of rest) {
+		for (let prop in src) {
+			const value = src[prop];
+			const oldValue = to[prop];
+			if (typeof value === 'object' && !Array.isArray(value)) {
+				if (typeof oldValue !== 'object') {
+					to[prop] = {};
+					updated = true;
+				}
+				updated = deepAssign(to[prop], value) || updated;
+			} else if (value === undefined && to[prop] !== undefined) {
+				delete to[prop];
+			} else if (value !== oldValue) {
+				updated = true;
+				to[prop] = value;
+			}
+		}
+	}
+	return updated;
+}
+
+export const pouchDocHash = d => (isObject(d) ? `${d._id}:${d._rev}` : d);
+export const pouchDocArrayHash = arr =>
+	Array.isArray(arr) ? arr.map(pouchDocHash).join('?') : arr;
+
+export function isObject(obj) {
+	return typeof obj === 'object' && !Array.isArray(obj) && obj !== null;
+}
diff --git a/packages/pouchtype/src/watcher.js b/packages/pouchtype/src/watcher.js
new file mode 100644
index 0000000..52463c4
--- /dev/null
+++ b/packages/pouchtype/src/watcher.js
@@ -0,0 +1,37 @@
+export function Watcher(db, selector, opts) {
+	const subscribers = new Set();
+	let changes = null;
+
+	return function subscribe(fn) {
+		subscribers.add(fn);
+
+		if (subscribers.size === 1 && !changes) {
+			changes = db
+				.changes(
+					Object.assign(
+						{
+							since: 'now',
+							live: true,
+							selector
+						},
+						opts
+					)
+				)
+				.on('change', change => {
+					const { id, deleted, doc } = change;
+					subscribers.forEach(s => s(id, !!deleted, doc));
+				})
+				.on('error', err => {
+					subscribers.clear();
+					throw err;
+				});
+		}
+		return () => {
+			subscribers.delete(fn);
+			if (subscribers.size === 0 && changes) {
+				changes.cancel();
+				changes = null;
+			}
+		};
+	};
+}
diff --git a/packages/pouchtype/test.json b/packages/pouchtype/test.json
new file mode 100644
index 0000000..2ed9e5a
--- /dev/null
+++ b/packages/pouchtype/test.json
@@ -0,0 +1,9 @@
+{
+	"spec_dir": "spec",
+	"spec_files": ["**/*[sS]pec.js"],
+	"lib_files": [
+		"node_modules/pouchdb/dist/pouchdb.js",
+		"node_modules/pouchdb/dist/pouchdb.memory.js",
+		"node_modules/pouchdb/dist/pouchdb.find.js"
+	]
+}