Avoid trueTime.now() throwing errors (#110)

* Avoid trueTime.now() throwing errors

As it gets tricky to work with, this proposes to always return a time, even if that can be off initially.

Also makes the module try to synchronize itself as early as possible, and tries to avoid double sync network calls.

eslint.config.js

@@ -48,7 +48,7 @@ export default [
       'no-restricted-syntax': [
         'error',
         {
-          message: 'Never use Date.now! always use TrueTime',
+          message: 'Never use Date.now! always use trueTime.now()',
           selector:
             'CallExpression[callee.object.name="Date"][callee.property.name="now"]',
         },

packages/player/src/internal/true-time.ts

@@ -1,3 +1 @@
-import { TrueTime } from '@tidal-music/true-time';
-
-export const trueTime = new TrueTime('https://api.tidal.com/v1/ping');
+export { trueTime } from '@tidal-music/true-time';

packages/true-time/src/index.test.ts

@@ -66,36 +66,10 @@ describe('TrueTime', () => {
     });
   });
 
-  describe('true time errors', () => {
-    const trueTime = new TrueTime('https://api.tidal.com/v1/ping');
-
-    describe('now', () => {
-      test('throws error due to no synchronize call', async () => {
-        expect(() => trueTime.now()).toThrowError(
-          'Initialization has not been done yet. You need to call and await the synchronize method once.',
-        );
-      });
-    });
-
-    describe('timestamp', () => {
-      test('throws error due to no synchronize call', async () => {
-        // PS `performance.mark` should not be called without `startTime: trueTime.now()` option,
-        // but doing it here to test the error.
-        performance.mark('birds are dinosaurs');
-
-        expect(() => trueTime.timestamp('birds are dinosaurs')).toThrowError(
-          'Initialization has not been done yet. You need to call and await the synchronize method once.',
-        );
-      });
-    });
-  });
-
   describe('google true time', () => {
-    const trueTime = new TrueTime('https://time.google.com');
-
     test('fetches server time from correct url', async () => {
       vi.spyOn(globalThis, 'fetch');
-      await trueTime.synchronize();
+      new TrueTime('https://time.google.com');
 
       const callArg = vi.mocked(fetch)?.mock.calls[0]?.[0] as URL;
       expect(callArg?.href).toEqual('https://time.google.com/');

packages/true-time/src/index.ts

@@ -1,27 +1,28 @@
 export class TrueTime {
   #clientStartTime?: number;
 
+  #isSynchronizing = false;
+
   #serverTime?: number;
 
   #url: URL;
 
   constructor(url: string) {
     this.#url = new URL(url);
+    void this.synchronize();
   }
 
   /**
    * Returns the current time adjusted to server-time.
    *
    * @param clientCurrentTime The current time on the client side. Defaults to Date.now().
-   * @returns The current adjusted time.
-   * @throws {ReferenceError} If the initialization has not been done yet. You need to call and await the `synchronize` method once.
+   * @returns The current adjusted time (or the client time if not synced yet).
    */
   // eslint-disable-next-line no-restricted-syntax
   now(clientCurrentTime = Date.now()): number {
     if (!this.#serverTime || !this.#clientStartTime) {
-      throw new ReferenceError(
-        'Initialization has not been done yet. You need to call and await the synchronize method once.',
-      );
+      console.warn('TrueTime is not yet synchronized');
+      return clientCurrentTime;
     }
 
     return this.#serverTime + (clientCurrentTime - this.#clientStartTime);
@@ -37,13 +38,15 @@ export class TrueTime {
     const anHour = 3_600_000;
 
     if (
-      this.#clientStartTime &&
-      // eslint-disable-next-line no-restricted-syntax
-      Math.abs(Date.now() - this.#clientStartTime) < anHour
+      (this.#clientStartTime &&
+        // eslint-disable-next-line no-restricted-syntax
+        Math.abs(Date.now() - this.#clientStartTime) < anHour) ||
+      this.#isSynchronizing
     ) {
       return;
     }
 
+    this.#isSynchronizing = true;
     try {
       const response = await fetch(this.#url);
 
@@ -55,6 +58,7 @@ export class TrueTime {
     } catch (error) {
       console.error(error);
     }
+    this.#isSynchronizing = false;
   }
 
   /**
@@ -64,17 +68,11 @@ export class TrueTime {
    * @param markName - The name of the performance mark.
    * @param detail - Optional. The detail of the performance mark.
    * @returns The timestamp of the performance mark, or undefined if not found.
-   * @throws ReferenceError if initialization has not been done yet or if the performance mark is not found.
+   * @throws ReferenceError if the performance mark is not found.
    */
   timestamp(markName: string, detail?: string): number | undefined {
     let performanceEntry: PerformanceEntry | undefined;
 
-    if (!this.#serverTime || !this.#clientStartTime) {
-      throw new ReferenceError(
-        'Initialization has not been done yet. You need to call and await the synchronize method once.',
-      );
-    }
-
     if (detail) {
       performanceEntry = performance
         .getEntriesByName(markName)