Add passed status manager

static/js/passedState.js

@@ -0,0 +1,43 @@
+
+
+class PassedState {
+    constructor(initialState = {}) {
+        const currentState = localStorage.getItem('passedState');
+        // initialize the state when there is no state in the local storage.
+        if (!currentState) {
+            if (!initialState) {
+                throw new Error('initial state is required when there is no state in the local storage.');
+            }
+
+            const state = this._prepareState(initialState);
+            localStorage.setItem('passedState', JSON.stringify(state));
+            this.state = state;
+            return;
+        }
+
+        if (currentState) {
+            this.state = JSON.parse(currentState);
+        }
+    }
+
+    /**
+     * prepare the state for initialization.
+     * @param {object} rawState 
+     * @returns state - the state contains the challenge name and whether the challenge is passed.
+     */
+    _prepareState(rawState) {
+        const state = {};
+        for (const level in rawState) {
+            const challenges = [];
+            for (const challengeName of rawState[level]) {
+                challenges.push({
+                    name: challengeName,
+                    passed: false
+                });
+            }
+            state[level] = challenges;
+        }
+
+        return state;
+    }
+}