Make session expiry checking function more generic, allow custom timeout

Author: rosahbruno

glean/src/core/internal_metrics.ts

@@ -13,7 +13,7 @@ import { generateUUIDv4, isWindowObjectUnavailable } from "./utils.js";
 import { Lifetime } from "./metrics/lifetime.js";
 import log, { LoggingLevel } from "./log.js";
 import { Context } from "./context.js";
-import { hasSessionBeenInactiveForOverThirtyMinutes } from "./sessions.js";
+import { isSessionInactive } from "./sessions.js";
 
 const LOG_TAG = "core.InternalMetrics";
 
@@ -193,11 +193,10 @@ export class CoreMetrics {
    * 1. If this is the first session (there is no existing session ID),
    * then we set a new session ID and a lastActive timestamp.
    *
-   * 2. If the lastActive time is under 30 minutes, then we only update
-   * the lastActive time.
+   * 2. If the session is not expired, then we only update the lastActive time.
    *
-   * 3. If the lastActive time is over 30 minutes, then we update the
-   * session ID, the session sequence number, and the lastActive time.
+   * 3. If the session is expired (inactive threshold is more recent than lastActive)
+   * then we update the session ID, the session sequence number, and the lastActive time.
    */
   updateSessionInfo(): void {
     if (isWindowObjectUnavailable()) {
@@ -211,9 +210,8 @@ export class CoreMetrics {
 
     if (existingSessionId) {
       try {
-        // If over 30 minutes has passed since last session interaction,
-        // then we create a new session.
-        if (hasSessionBeenInactiveForOverThirtyMinutes()) {
+        // If the session has timed out, then we create a new session.
+        if (isSessionInactive()) {
           this.generateNewSession();
         }
       } catch (e) {

glean/src/core/sessions.ts

@@ -3,22 +3,19 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /**
- * Check if the current session has been inactive for over thirty minutes. If
- * it has, then we create a new session.
+ * Check if the current session is inactive - the default timeout is 30 minutes.
  *
- * @returns {boolean} If the session has been inactive for over thirty minutes.
+ * @param sessionLengthInMinutes Length of the session in minutes - defaults to 30.
+ * @returns {boolean} If the current session is inactive.
  */
-export function hasSessionBeenInactiveForOverThirtyMinutes(): boolean {
+export function isSessionInactive(sessionLengthInMinutes = 30): boolean {
   const lastActive = localStorage.getItem("glean_session_last_active");
   const lastActiveDate = new Date(Number(lastActive));
 
-  // Create a date 30 minutes ago to compare to our lastActiveDate.
-  //
-  // 60000 - number of milliseconds in a minute
-  // 30 - the number of minutes that can pass before a session is inactive
-  const thirtyMinutesAgo = new Date(Date.now() - (60000 * 30));
+  // Subtract the session length from the current date
+  const inactiveThreshold = new Date(Date.now() - (60000 * sessionLengthInMinutes));
 
-  // If the date we created from 30 minutes ago is more recent than the last
-  // active date, then the current session has expired.
-  return thirtyMinutesAgo > lastActiveDate;
+  // If the inactiveThreshold is more recent than the lastActiveDate, then the
+  // current session is expired.
+  return inactiveThreshold > lastActiveDate;
 }