Added selectById

README.md

@@ -46,6 +46,7 @@
   - [`close()`](#close)
   - [`insert()`](#insert)
   - [`select()`](#select)
+  - [`selectById()`][#select-by-id]
   - [`update()`](#update)
   - [`delete()`](#delete)
   - [`drop()`](#drop)
@@ -254,6 +255,21 @@ const docs = db.select({ name: 'Mipha' });
 const docs = db.select({ name: 'Mipha' }, { name: 'Tulin' });
 ```
 
+### `selectById()`
+
+Find document(s) based on `_id`. Multiple ids can be used.
+
+```TS
+import LeafDB from 'leaf-db';
+
+const db = new LeafDB('db');
+
+// Return docs where `_id` is equal to `Mipha`
+const docs = db.selectById('Mipha');
+// Return docs where `_id` is equal to `Mipha` or where `_id` is equal to `Tulin`
+const docs = db.selectById('Mipha', 'Tulin');
+```
+
 ### `update()`
 
 Update document(s) based on [query](#queries). Multiple queries can be used. Updated document cannot change shape.

src/model.ts

@@ -115,6 +115,14 @@ export default class LeafDB<T extends Draft> {
     return docs;
   }
 
+  selectById(...ids: string[]) {
+    return ids.reduce<Array<Doc<T>>>((acc, cur) => {
+      const doc = this._memory.get(cur);
+      if (doc) acc.push(doc);
+      return acc;
+    }, []);
+  }
+
   update(update: Update<Doc<T>>, ...queries: Array<Query<Doc<T>>>) {
     if ('_id' in update) throw new Error('Invalid update, cannot contain key `_id`');
 

test/unit/model/model.selectById.spec.ts

@@ -0,0 +1,24 @@
+import test from 'tape';
+
+import type { Doc } from './fixture';
+import setup, { memory } from './fixture';
+
+test('[model.selectById] returns docs on empty query', t => {
+  const { db } = setup<Doc>({ memory });
+
+  const docs = db.selectById();
+  t.true(Array.isArray(docs), 'is array');
+  t.strictEqual(docs.length, 0, 'finds docs (empty)');
+
+  t.end();
+});
+
+test('[model.selectById] returns docs on id match', t => {
+  const { db } = setup<Doc>({ memory });
+
+  const docs = db.selectById('2', '6');
+  t.strictEqual(docs.length, 2, 'finds docs');
+  t.strictEqual(docs[0].name, 'Aarhus', 'finds correct docs');
+
+  t.end();
+});