Add lib/options module for typed/easier options storage access

ext/src/lib/options.ts

@@ -0,0 +1,54 @@
+"use strict";
+
+import { Options } from "../defaultOptions";
+
+
+/**
+ * Fetches `options` key from storage and returns it as
+ * Options interface type.
+ */
+async function getAll (): Promise<Options> {
+    const { options }: { options: Options } =
+            await browser.storage.sync.get("options");
+
+    return options;
+}
+
+/**
+ * Takes Options object and sets to `options` storage key.
+ * Returns storage promise.
+ */
+async function setAll (options: Options): Promise<void> {
+    return browser.storage.sync.set({ options });
+}
+
+/**
+ * Gets specific option from storage and returns it as its
+ * type from Options interface type.
+ */
+async function get<T extends keyof Options> (name: T): Promise<Options[T]> {
+    const options = await getAll();
+
+    if (options.hasOwnProperty(name)) {
+        return options[name];
+    }
+}
+
+/**
+ * Sets specific option to storage. Returns storage
+ * promise.
+ */
+async function set<T extends keyof Options> (
+        name: T
+      , value: Options[T]): Promise<void> {
+
+    const options = await getAll();
+    options[name] = value;
+    return setAll(options);
+}
+
+
+export default {
+    get, getAll
+  , set, setAll
+}