Add configuration option to disable lazy loading of session replay recorder module

[asif-st-republic]

Problem

The Datadog RUM SDK lazy-loads the session replay recorder module using dynamic import(), which causes issues in environments that don't support code splitting or dynamic chunk loading, such as:

• Rails asset pipeline (Sprockets)
• Legacy webpack configurations without chunkFilename configured
• Build systems that require all assets to be declared in a manifest

When session replay is enabled (sessionReplaySampleRate > 0), the SDK attempts to fetch the recorder module at runtime:

GET /assets/startRecording

This results in a 404 error and session replay fails to initialize:

Datadog Browser SDK: Recorder failed to start: an error occurred while initializing the module: 
TypeError: Failed to fetch dynamically imported module: https://example.com/assets/startRecording

Requested Feature

Add a configuration option to the datadogRum.init() call that statically bundles the recorder module instead of lazy-loading it:

datadogRum.init({
  applicationId: 'xxx',
  clientToken: 'xxx',
  site: 'datadoghq.com',
  service: 'my-app',
  sessionReplaySampleRate: 100,
  // NEW OPTION:
  bundleRecorderModule: true // or lazyLoadRecorder: false
})

When this option is enabled, the SDK should:

1. Import the recorder module statically at build time
2. Skip the dynamic import() call
3. Use the bundled recorder directly

Workarounds

Currently, the only workarounds are:

1. Disable session replay entirely (sessionReplaySampleRate: 0)
2. Suppress console errors (poor UX)
3. Migrate to a different build system (significant effort)

Environment

• Browser: All
• SDK Version: @datadog/browser-rum 6.23.0
• Build System: Rails asset pipeline (Sprockets)
• Webpack: 4.x without code splitting configured

Impact

This affects any application using Rails, Django, or other traditional server-rendered frameworks with asset pipelines that don't support dynamic module loading.

[amortemousque]

Hello @asif-st-republic ,

Thanks for reporting this. For context, we added code-splitting to reduce the SDK overhead on the host app. The browser now downloads only what it needs, which improves load time. Most bundlers support code-splitting today, so we rely on it.

In your case, Webpack 4 supports code-splitting as well (see doc). Can you explain how you disabled code-splitting and why, so we can help you? If you prefer not to post your config here, you can contact support.

You can also choose one of these options:

• Use the CDN setup described in our docs.
• Stay on the v5 NPM version.