`run_javascript`

RunJavaScript is a campaign node that executes custom business logic inside the ResultFly runtime. The node consumes the current State and campaign context, computes a result, and applies approved changes to declared variables before the flow continues. It exists to adapt campaign rules on the fly—not to replace API integrations or external services.

Summary

Placement: Mid-flow.
Context: Client and backend apps (executes inside the managed runtime).
Visual: No.
Level: Advanced.
Purpose: Run bespoke campaign logic that depends on declared State without involving external APIs.

What RunJavaScript Does

Runs as part of the campaign flow, between other nodes.
Executes in a controlled ResultFly environment with access to the same State the rest of the campaign uses.
Receives the live State as input and produces calculated values or State updates through sanctioned operations.
Keeps all logic server-side; nothing runs in the user’s browser.

RunJavaScript vs API Integrations

Use API Integrations when…	Use RunJavaScript when…
Data originates in external systems (CRM, POS, loyalty backends).	Logic depends purely on the campaign’s current State.
Business rules must live in the brand’s backend or middleware.	Marketers need to adjust rules frequently without redeploying backend code.
A server-to-server conversation is required (webhooks, file drops, event ingestion).	The flow needs inline calculations, conditional branching, or normalization before choosing the next node.

RunJavaScript complements APIs: external events and service calls bring data into ResultFly, while RunJavaScript shapes decisions using that data inside the runtime.

Working with State

The node reads declared variables across all scopes:

state.user.* — user-level data shared across campaigns.
state.campaign.* — campaign-specific variables.
state.app.* — variables tied to the current app or game.

Updates must follow State rules:

Only declared variables may change.
System fields (for example state.sessionId or runtime pointers) are off-limits.
New variables cannot be created during execution; declare them before launch.

RunJavaScript applies mutations using the same mechanisms as other nodes, ensuring consistency with the State model.

Typical Use Cases

Bonus calculations. Combine multiple variables (spend, tier, streak) to determine how many points to award.
Advanced branching. Evaluate layered conditions to decide which storyline, prize, or limiter applies.
Data shaping. Transform external event attributes or user inputs into normalized State values before downstream nodes consume them.

Limitations and Guarantees

Code executes in an isolated, sandboxed environment controlled by ResultFly.
No direct network access; outbound calls are blocked unless explicitly provided by another node.
Execution time is limited to keep the campaign responsive; long loops or blocking logic will fail.
RunJavaScript is part of the deterministic campaign runtime—every execution is audited alongside other nodes.

What RunJavaScript Is NOT

It is not a replacement for the brand’s backend or microservices.
It is not an API endpoint or webhook target.
It is not a substitute for external events or server-to-server integrations.
It is not a loophole to bypass State rules or create ad-hoc storage.

Relationship to Other Concepts

Identity. Determines which user’s State the node reads and updates.
External Events. May trigger a flow that includes RunJavaScript, ensuring external signals feed into on-platform logic.
State & Variables. Provide the structured data the node consumes and mutates.
API Integrations. Handle communication outside ResultFly, delivering the data that RunJavaScript leverages during execution.