Import other modules into monorepo

src/util/cache/Cache.ts

@@ -0,0 +1,33 @@
+import {Awaitable} from "../support/types"
+
+/**
+ * Abstract interface class for a cached object.
+ */
+export abstract class Cache {
+    /**
+     * Fetch a value from the cache by its key.
+     * @param {string} key
+     * @return Promise<any|undefined>
+     */
+    public abstract fetch(key: string): Awaitable<string|undefined>;
+
+    /**
+     * Store the given value in the cache by key.
+     * @param {string} key
+     * @param {string} value
+     */
+    public abstract put(key: string, value: string): Awaitable<void>;
+
+    /**
+     * Check if the cache has the given key.
+     * @param {string} key
+     * @return Promise<boolean>
+     */
+    public abstract has(key: string): Awaitable<boolean>;
+
+    /**
+     * Drop the given key from the cache.
+     * @param {string} key
+     */
+    public abstract drop(key: string): Awaitable<void>;
+}