Method loadCacheFromDisk

src/node/services/experimentsService.ts:329–383

()

  }

  private async loadCacheFromDisk(): Promise<void> {
    try {
      const raw = await fs.readFile(this.cacheFilePath, "utf-8");
      const parsed = JSON.parse(raw) as unknown;

      if (!isRecord(parsed)) {
        return;
      }

      const version = parsed.version;
      const experiments = parsed.experiments;
      const overrides = parsed.overrides;

      if (version !== CACHE_FILE_VERSION || !isRecord(experiments)) {
        return;
      }

      for (const [key, value] of Object.entries(experiments)) {
        if (!(key in EXPERIMENTS) || !isRecord(value)) {
          continue;
        }

        const fetchedAtMs = value.fetchedAtMs;
        const variant = value.value;

        if (typeof fetchedAtMs !== "number" || !Number.isFinite(fetchedAtMs)) {
          continue;
        }

        if (typeof variant !== "string" && typeof variant !== "boolean") {
          continue;
        }

        this.cachedVariants.set(key as ExperimentId, {
          value: variant,
          fetchedAtMs,
          source: "cache",
        });
      }

      if (!isRecord(overrides)) {
        return;
      }

      for (const [key, value] of Object.entries(overrides)) {
        if (!(key in EXPERIMENTS) || typeof value !== "boolean") {
          continue;
        }

        this.overrides.set(key as ExperimentId, value);
      }
    } catch {
      // Ignore missing/corrupt cache
    }
  }

  private async writeCacheToDisk(): Promise<void> {
    try {