index.js

// [SNIPPET_REGISTRY disabled]
// [SNIPPETS_SEPARATION enabled]

const perf = getInstance();

function intialize() {
  // [START perf_import_app]
  const { initializeApp } = require("firebase/app");
  // [END perf_import_app]
  // [START perf_import]
  const { getPerformance } = require("firebase/performance");
  // [END perf_import]

  // [START perf_initialize_app]
  // TODO: Replace the following with your app's Firebase project configuration
  // See: https://firebase.google.com/docs/web/learn-more#config-object
  const firebaseConfig = {
    // ...
  };

  // Initialize Firebase
  const app = initializeApp(firebaseConfig);
  // [END perf_initialize_app]

  // [START perf_singleton]
  // Initialize Performance Monitoring and get a reference to the service
  const perf = getPerformance(app);
  // [END perf_singleton]
}

export function getInstance() {
  // [START perf_get_instance]
  const { getPerformance } = require("firebase/performance");
  const perf = getPerformance();
  // [END perf_get_instance]

  return perf;
}

export function addCustomTrace() {
  // [START perf_add_custom_trace]
  const { trace } = require("firebase/performance");

  const t = trace(perf, "CUSTOM_TRACE_NAME");
  t.start();

  // Code that you want to trace 
  // ...

  t.stop();
  // [END perf_add_custom_trace]
}

export function userTimingMarks() {
  // [START perf_user_timing_marks]
  const performance = window.performance;
  
  performance.mark("measurementStart");

  // Code that you want to trace 
  // ...

  performance.mark("measurementStop");
  performance.measure("customTraceName", "measurementStart", "measurementStop");
  // [END perf_user_timing_marks]
}

export function addCustomAttributes() {
  // [START perf_add_custom_attributes]
  const { trace } = require("firebase/performance");

  const t = trace(perf, "test_trace");
  t.putAttribute("experiment", "A");

  // Update scenario
  t.putAttribute("experiment", "B");

  // Reading scenario
  const experimentValue = t.getAttribute("experiment");

  // Delete scenario
  t.removeAttribute("experiment");

  // Read attributes
  const traceAttributes = t.getAttributes();
  // [END perf_add_custom_attributes]
}

export function addCustomMetrics() {
  async function retrieveInventory(inventoryIds) {
    return {};
  }

  // [START perf_add_custom_metrics]
  const { trace } = require("firebase/performance");

  async function getInventory(inventoryIds) {
    const t = trace(perf, "inventoryRetrieval");
  
    // Tracks the number of IDs fetched (the metric could help you to optimize in the future)
    t.incrementMetric("numberOfIds", inventoryIds.length);
  
    // Measures the time it takes to request inventory based on the amount of inventory
    t.start();
    const inventoryData = await retrieveInventory(inventoryIds);
    t.stop();
  
    return inventoryData;
  }
  // [END perf_add_custom_metrics]
}