Journey Definition Resolver

Source file: packages/core/src/journey-machine/resolve-journey-definition.ts

This file turns authored transition shapes into the one runtime shape the machine actually executes: an ordered array of transitions.

How It Works

1. If journey.transitions is missing, the resolver returns the journey with an empty transition list.
2. If transitions were authored as an array, the file treats that as a linear journey declaration. It validates that every entry is a known step id, checks that the first item matches journey.initial, and expands the array into implicit goToNextStep edges.
3. If transitions were authored as an object graph, the file validates each from -> event -> edges[] layer and flattens it into ordered transition objects.
4. Every named step branch is resolved first and keeps its step id. The global branch is resolved last and rewritten to from: "*", so it behaves as a fallback bucket after step-local transitions for the same event.
5. The original journey object is returned with transitions replaced by that normalized array.

The important guarantee is ordering. send.ts scans transitions in order, so the resolver preserves author intent while still giving the runtime one deterministic structure to evaluate.

Recommended Reading

• Read Send Pipeline to see how the ordered transition list is consumed.
• Read Transitions Syntax for the public authoring shapes this file accepts.
• Read Quickstart if you want to compare the normalized behavior with authored examples.