feat(js): implement bidi actions and flows

[pavelgj]

RFC: #4210

Checklist (if applicable):

• PR title is following https://www.conventionalcommits.org/en/v1.0.0/
• Tested (manually, unit tested, etc.)
• Docs updated (updated docs or a docs bug required)

[gemini-code-assist]

Summary of Changes

Hello @pavelgj, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the framework by introducing comprehensive support for bi-directional actions and flows. This new capability allows for interactive, real-time communication patterns, such as chat-like interfaces, where both the client and the server-side action/flow can send and receive data asynchronously. The changes involve extending core interfaces, adding new functions for defining these bi-directional components, and ensuring robust input and initialization data validation, all backed by new test suites.

Highlights

• Bi-directional Action and Flow Support: Introduced new interfaces and functions (BidiStreamingResponse, streamBidi, defineBidiAction, bidiAction, defineBidiFlow, bidiFlow) to enable bi-directional streaming for actions and flows.
• Enhanced Type Safety and Configuration: Updated ActionRunOptions, ActionFnArg, Action, Flow, and FlowConfig with generic types for input streams and initialization data (I, Init), and added initSchema for configuration.
• Input and Initialization Data Validation: Implemented schema validation for both streaming input (inputStream) and initial configuration data (init) within bi-directional actions and flows.
• New Test Coverage: Added dedicated test files (bidi-action_test.ts, bidi-flow_test.ts) to thoroughly validate the new bi-directional streaming capabilities, including push/pull mechanisms, classic run compatibility, and data validation.

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[gemini-code-assist]

Code Review

This pull request introduces a significant and well-implemented feature: support for bidirectional streaming in actions and flows. The changes correctly extend core interfaces like Action, ActionRunOptions, and ActionFnArg to handle streaming inputs and initialization data. The new factory functions bidiAction and bidiFlow are consistent with existing patterns, and the feature is supported by a comprehensive new test suite.

My review focuses on improving type safety by correcting several incomplete or incorrect type assertions in the new implementation. These adjustments will enhance code robustness and maintainability. I've also noted a minor, potentially out-of-scope change in registry.ts and a small typing improvement for a new helper function. Overall, this is a solid contribution.

[pavelgj]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces significant new functionality by implementing bi-directional actions and flows. The changes are extensive, touching core action and flow definitions, and include new APIs like streamBidi, defineBidiAction, and defineBidiFlow. The addition of init data for actions is also a valuable enhancement. The implementation is well-structured, reusing action to build bidiAction, and bidiAction to build bidiFlow. The accompanying tests are thorough and cover various use cases, including push/pull streaming, init data, and validation. I have a few suggestions to improve code clarity and remove some redundant logic in the core action.ts file.

[gemini-code-assist]

Code Review

The code changes introduce bi-directional streaming actions and flows, including new interfaces and functions for defining and handling them. The changes include adding BidiStreamingResponse interface, updating Action and ActionFnArg types to support bi-directional streaming, and introducing defineBidiAction and bidiAction functions. The code also updates the FlowConfig interface and introduces defineBidiFlow and bidiFlow functions. The type cast (opts as ActionFnArg<...>) was corrected to directly access opts?.init for type safety.