Add data_visualization/js/api.js

data_visualization/js/api.js

@@ -0,0 +1,52 @@
+/**
+ * js/api.js
+ * Data layer for fetching measurement data (temperature & audio) from the backend API.
+ *
+ * @module api
+ */
+
+/**
+ * Builds a query string from optional parameters.
+ * @param {Object} [params={}] - Optional query parameters.
+ * @returns {string} Query string starting with '?', or empty string if no params.
+ */
+function buildQueryString(params = {}) {
+  const query = Object.entries(params)
+    .filter(([_, v]) => v != null && v !== '')
+    .map(([k, v]) => `${encodeURIComponent(k)}=${encodeURIComponent(v)}`)
+    .join('&');
+  return query ? `?${query}` : '';
+}
+
+/**
+ * Fetches measurement data from the /data API endpoint.
+ *
+ * @async
+ * @param {Object} [filters] - Optional filters, e.g. { sensorType: 'temperature', timeRange: '24h' }.
+ * @returns {Promise<Object>} Resolves with parsed JSON { temperature: [...], audio: [...] }.
+ * @throws Will throw an error if the fetch response is not OK or JSON is invalid.
+ */
+export async function fetchData(filters = {}) {
+  const queryString = buildQueryString(filters);
+  const url = `/data${queryString}`;
+
+  try {
+    const response = await fetch(url, { method: 'GET', headers: { 'Accept': 'application/json' } });
+
+    if (!response.ok) {
+      throw new Error(`Fetch error: ${response.status} ${response.statusText}`);
+    }
+
+    const data = await response.json();
+
+    // Defensive checks
+    if (!data || typeof data !== 'object' || !Array.isArray(data.temperature) || !Array.isArray(data.audio)) {
+      throw new Error('Invalid data format from API');
+    }
+
+    return data;
+  } catch (error) {
+    console.error('Error fetching data:', error);
+    throw error;
+  }
+}