Manage order with sorts and indexing rather than keys

The jury is still out on this.  Indexes are the "right" way to do this but are actually slower in some circumstances.

packages/gallery/src/data/image.js

@@ -25,10 +25,6 @@ class ImageSpec extends TypeSpec {
 		return doc.digest.substr(0, 16);
 	}
 
-	static getSequence(doc) {
-		return new Date(doc.originalDate).getTime();
-	}
-
 	async delete(cascade = true) {
 		if (cascade) {
 			new Set(Object.keys(this.sizes)).forEach(async key => {
@@ -126,4 +122,6 @@ const processImportables = backgroundTask(async function _processImportables(ima
 
 export const ImageType = PouchDB.registerType('Image', ImageSpec);
 
+ImageType.index('originalDate', ['originalDate', 'id']);
+
 ImageType.find({ importing: true }).then(results => results.forEach(processImportables));

packages/gallery/src/interface/focus.js

@@ -107,10 +107,32 @@ export function FocusView(vm, params) {
 					}
 					doc(await ImageType.find(_id));
 
-					const n = await ImageType.next(_id);
+					const n = await ImageType.find(
-					nextLink(n.length ? router.href('focus', { id: n[0].id }) : null);
+						{
-					const p = await ImageType.next(_id, true);
+							originalDate: { $gte: doc().originalDate }
-					prevLink(p.length ? router.href('focus', { id: p[0].id }) : null);
+						},
+						{
+							limit: 1,
+							skip: 1,
+							index: 'originalDate',
+							sort: [{ originalDate: 'asc' }]
+						}
+					);
+
+					const p = await ImageType.find(
+						{
+							originalDate: { $lte: doc().originalDate }
+						},
+						{
+							limit: 1,
+							skip: 1,
+							index: 'originalDate',
+							sort: [{ originalDate: 'desc' }]
+						}
+					);
+
+					nextLink(n.length ? router.href('focus', { id: n[0]._id }) : null);
+					prevLink(p.length ? router.href('focus', { id: p[0]._id }) : null);
 				})
 		],
 		true

packages/gallery/src/interface/sectionView.js

@@ -60,6 +60,8 @@ export function SectionView(vm, params, key) {
 		[photoArray, availableViewportSize]
 	);
 
+	photos.sort((a, b) => a.originalDate.localeCompare(b.originalDate));
+
 	subscribeToRender(vm, [sections]);
 
 	return function render(vm, params) {

packages/gallery/src/services/db.js

@@ -23,10 +23,6 @@ export class TypeSpec {
 		Object.assign(this, { $links: {} }, props, { type: this._prefix });
 	}
 
-	static getSequence(doc) {
-		return '';
-	}
-
 	static getUniqueID(doc) {
 		throw 'NotImplemented';
 	}
@@ -39,7 +35,7 @@ export class TypeSpec {
 
 	_populateId(doc) {
 		if (!doc._id) {
-			doc._id = `${this._prefix}_${this._cls.getSequence(doc)}_${this._cls.getUniqueID(doc)}`;
+			doc._id = `${this._prefix}_${this._cls.getUniqueID(doc)}`;
 		}
 		return doc;
 	}
@@ -116,6 +112,10 @@ export function PouchORM(PouchDB) {
 				isSelector && idOrSelector._deleted ? { _deleted: true } : { _deleted: { exists: false } },
 				isSelector ? idOrSelector : _baseSelector
 			);
+			if (opts.index) {
+				opts.use_index = [prefix, opts.index];
+				delete opts.index;
+			}
 			if (opts.live) {
 				opts.mapper = instantiate;
 				return LiveArray(_db, idOrSelector, opts);
@@ -148,15 +148,14 @@ export function PouchORM(PouchDB) {
 			}
 		}
 
-		async function next(key, previous = false, limit = 1, inclusive = false) {
+		async function _index(name, fields) {
-			const res = await _db.allDocs({
+			return _db.createIndex({
-				startkey: key,
+				index: {
-				descending: previous,
+					ddoc: prefix,
-				sort: ['id'],
+					fields,
-				skip: inclusive ? 0 : 1,
+					name
-				limit
+				}
 			});
-			return res.rows;
 		}
 
 		Object.defineProperties(cls.prototype, {
@@ -170,7 +169,7 @@ export function PouchORM(PouchDB) {
 		Object.defineProperties(cls, {
 			getOrCreate: { value: getOrCreate },
 			find: { value: find },
-			next: { value: next },
+			index: { value: _index },
 			delete: { value: _delete },
 			subscribe: { value: watch },
 			db: { value: _db },