priorityInit

By default, services within a module wire in the order they appear in the services object. If a service's top-level code (outside any lifecycle callback) needs another service's return value, the dependency must be wired first. priorityInit declares that order explicitly.

Usage

CreateApplication({
  name: "my_app",
  priorityInit: ["database", "cache"],  // wire these first, in this order
  services: {
    cache:    CacheService,    // ← wires second
    database: DatabaseService, // ← wires first
    api:      ApiService,      // ← wires after database and cache
    worker:   WorkerService,   // ← wires after api
  },
});

Services named in priorityInit wire first, in listed order. All remaining services wire after, in their declaration order.

The wireOrder algorithm

wireOrder(priority, allServices) produces the final wiring sequence:

1. Start with priority (in order)
2. Append any service in allServices not already in priority
3. Wire the combined list serially (one at a time, awaiting each)

This means priorityInit is purely additive — it doesn't remove any services, it just puts specific ones first.

When to use it

priorityInit is needed when a service accesses another service's return value at the top level of its function (during wiring), not inside a lifecycle callback:

// ❌ Can break if cache isn't wired yet
export function ApiService({ my_app }: TServiceParams) {
  const pool = my_app.database.createPool();  // top-level — runs during wiring
}

// ✅ Fix: declare database in priorityInit
CreateApplication({
  priorityInit: ["database"],
  services: { database: DatabaseService, api: ApiService },
});

// ✅ Alternative fix: move the call inside a lifecycle callback
export function ApiService({ my_app, lifecycle }: TServiceParams) {
  lifecycle.onBootstrap(() => {
    const pool = my_app.database.createPool();  // safe — all services wired
  });
}

Limitations

priorityInit only controls order within a module. It cannot make a library service wire before your application service. For cross-module ordering, use depends / libraries in CreateLibrary.

Error: DOUBLE_PRIORITY

If priorityInit contains the same service name more than once, wireOrder throws DOUBLE_PRIORITY immediately:

priorityInit: ["database", "cache", "database"] // ← DOUBLE_PRIORITY

Error: MISSING_PRIORITY_SERVICE

If a name in priorityInit doesn't exist in services, CreateApplication throws MISSING_PRIORITY_SERVICE at construction time (before bootstrap):

priorityInit: ["database"],
services: { db: DatabaseService } // ← "database" not in services → MISSING_PRIORITY_SERVICE