feat: add storage interface + implement indexedDb

Author: AmeanAsad

package-lock.json

@@ -28,6 +28,7 @@
     "@ipld/dag-pb": "^2.1.18",
     "@multiformats/blake2": "^1.0.11",
     "browser-readablestream-to-it": "^2.0.4",
+    "idb": "^7.1.1",
     "ipfs-unixfs-exporter": "https://gitpkg.now.sh/filecoin-saturn/js-ipfs-unixfs/packages/ipfs-unixfs-exporter?build",
     "multiformats": "^12.1.1"
   },

package.json

@@ -0,0 +1,38 @@
+// @ts-check
+
+import { openDB } from 'idb'
+
+const DEFAULT_IDB_VERSION = 1
+const DEFAULT_IDB_STORAGE_NAME = 'saturn-db'
+const DEFAULT_SATURN_STORAGE_NAME = 'saturn-client'
+
+/**
+ * @typedef {object} Storage
+ * @property {function():boolean} check - Checks if the provided Storage is accessible
+ * @property {function(string):Promise<any>} get - Retrieves the value associated with the key.
+ * @property {function(string,any):Promise<void>} set - Sets a new value for the key.
+ * @property {function(string):Promise<any>} delete - Deletes the value associated with the key.
+ */
+
+/**
+ * @function indexedDbStorage
+ * @returns {Storage}
+ */
+export function indexedDbStorage () {
+  const indexedDbExists = (typeof window !== 'undefined') && window?.indexedDB
+  let dbPromise
+  if (indexedDbExists) {
+    dbPromise = openDB(DEFAULT_IDB_STORAGE_NAME, DEFAULT_IDB_VERSION, {
+      upgrade (db) {
+        db.createObjectStore(DEFAULT_SATURN_STORAGE_NAME)
+      }
+    })
+  }
+
+  return {
+    check: () => Boolean(indexedDbExists),
+    get: async (key) => indexedDbExists && (await dbPromise).get(DEFAULT_SATURN_STORAGE_NAME, key),
+    set: async (key, value) => indexedDbExists && (await dbPromise).put(DEFAULT_SATURN_STORAGE_NAME, value, key),
+    delete: async (key) => indexedDbExists && (await dbPromise).delete(DEFAULT_SATURN_STORAGE_NAME, key)
+  }
+}