unfoldSchedule - API reference

API reference › @evolu/common › Schedule › unfoldSchedule

function unfoldSchedule<State>(
  initial: State,
  next: (state: State) => State,
): Schedule<State>;

Defined in: packages/common/src/Schedule.ts:541

Creates a schedule by unfolding a state.

Each step outputs the current state and computes the next state using the provided function. Never stops — combine with take or maxElapsed to limit.

Example

// Counter: 0, 1, 2, 3, ...
const counter = unfoldSchedule(0, (n) => n + 1);

// Custom backoff: 100, 150, 225, 338, ... (×1.5 each time)
const customBackoff = unfoldSchedule(100, (delay) => Math.round(delay * 1.5));

// State machine
type Phase = "init" | "warmup" | "active";
const phases = unfoldSchedule<Phase>("init", (phase) => {
  switch (phase) {
    case "init":
      return "warmup";
    case "warmup":
      return "active";
    case "active":
      return "active";
  }
});