From 7052380cffa27fba877be575dd46aeaee3b98e3a Mon Sep 17 00:00:00 2001
From: Pooya Parsa <pyapar@gmail.com>
Date: Thu, 11 Mar 2021 11:55:30 +0100
Subject: [PATCH] feat: snapshot

---
 README.md                               | 11 ++++++++++-
 src/storage.ts                          | 10 ++++++++++
 test/{index.test.ts => generic.test.ts} |  0
 test/snapshot.test.ts                   | 20 ++++++++++++++++++++
 4 files changed, 40 insertions(+), 1 deletion(-)
 rename test/{index.test.ts => generic.test.ts} (100%)
 create mode 100644 test/snapshot.test.ts

diff --git a/README.md b/README.md
index 8c09a7aa..b0f11e16 100644
--- a/README.md
+++ b/README.md
@@ -17,12 +17,12 @@
 - Tree-shakable and lightweight core
 - Native aware value serialization and deserialization
 - Restore initial state (hydration)
+- State snapshot
 
 WIP:
 
 - Unmount
 - Key expiration
-- State snapshot
 - State compression
 - Watcher
 
@@ -148,6 +148,15 @@ Removes all stored key/values. If a base is provided, only mounts matching base
 await storage.clear()
 ```
 
+### `snapshot(storage, base?)`
+
+Snapshot from all keys in specified base into a plain javascript object (string: string). Base is removed from keys.
+```js
+import { snapshot } from 'unstorage'
+
+const data = await snapshot(storage, '/etc')
+```
+
 ### `storage.dispose()`
 
 Disposes all mounted storages to ensure there are no open-handles left. Call it before exiting process.
diff --git a/src/storage.ts b/src/storage.ts
index 43f4fdfd..6a028bee 100644
--- a/src/storage.ts
+++ b/src/storage.ts
@@ -96,6 +96,16 @@ export function createStorage (): Storage {
   return storage
 }
 
+export async function snapshot (storage: Storage, base: string) {
+  base = normalizeBase(base)
+  const keys = await storage.getKeys(base)
+  const snapshot: any = {}
+  await Promise.all(keys.map(async (key) => {
+    snapshot[key.substr(base.length)] = await storage.getItem(key)
+  }))
+  return snapshot
+}
+
 async function dispose (storage: Driver) {
   if (typeof storage.dispose === 'function') {
     await asyncCall(storage.dispose)
diff --git a/test/index.test.ts b/test/generic.test.ts
similarity index 100%
rename from test/index.test.ts
rename to test/generic.test.ts
diff --git a/test/snapshot.test.ts b/test/snapshot.test.ts
new file mode 100644
index 00000000..4b7a8170
--- /dev/null
+++ b/test/snapshot.test.ts
@@ -0,0 +1,20 @@
+import { createStorage, snapshot } from '../src'
+
+const data = {
+  'etc:conf': 'test',
+  'data:foo': 'bar'
+}
+
+describe('snapshot', () => {
+  it('snapshot', async () => {
+    const storage = createStorage()
+    await storage.setItems('', data)
+    expect(await snapshot(storage, '')).toMatchObject(data)
+  })
+
+  it('snapshot (subpath)', async () => {
+    const storage = createStorage()
+    await storage.setItems('', data)
+    expect(await snapshot(storage, 'etc')).toMatchObject({ conf: 'test' })
+  })
+})