CLose story 1.2

src/contracts/pending-op.js

@@ -0,0 +1,83 @@
+/**
+ * PendingOp contract.
+ *
+ * A PendingOp tracks an in-flight visibility state change from the moment
+ * the GM issues the intent until the authoritative echo is received (or
+ * the 3-second timeout fires and triggers a revert).
+ *
+ * Lifecycle:
+ *   create → register in Map<opId, PendingOp>
+ *   echo received → delete from map + clearTimeout(timeoutId)
+ *   3s timeout fires → revert to previousState + GM notification
+ *
+ * @module contracts/pending-op
+ */
+
+/** @typedef {Object} PendingOp */
+
+/** Shape version constant for PendingOp. @type {1} */
+export const PENDING_OP_VERSION = 1;
+
+/**
+ * @typedef {Object} PendingOp
+ * @property {string} opId - Unique operation identifier (non-empty string).
+ * @property {string} userId - Target participant userId (non-empty string).
+ * @property {string} targetState - Desired VisibilityState (non-empty string).
+ * @property {string} previousState - State before this op; used for revert (non-empty string).
+ * @property {number} issuedAt - Timestamp (ms) when op was issued — Date.now() integer.
+ * @property {number|null} timeoutId - setTimeout handle; null if timeout not yet set.
+ */
+
+/**
+ * Creates a new PendingOp.
+ * @param {string} opId - Unique operation identifier.
+ * @param {string} userId - Target participant userId.
+ * @param {string} targetState - Desired VisibilityState.
+ * @param {string} previousState - State before this op.
+ * @param {number} [issuedAt] - Timestamp; defaults to Date.now().
+ * @returns {PendingOp}
+ */
+export function createPendingOp(opId, userId, targetState, previousState, issuedAt = Date.now()) {
+  return { opId, userId, targetState, previousState, issuedAt, timeoutId: null };
+}
+
+/**
+ * Validates a PendingOp DTO. Throws TypeError on any violation.
+ * @param {unknown} data - Value to validate.
+ * @returns {PendingOp} The validated PendingOp.
+ * @throws {TypeError} If data fails validation.
+ */
+export function isValidPendingOp(data) {
+  if (data === null || typeof data !== "object") {
+    throw new TypeError("PendingOp: must be an object");
+  }
+  const obj = /** @type {Record<string, unknown>} */ (data);
+  const { opId, userId, targetState, previousState, issuedAt, timeoutId, ...rest } = obj;
+  if (Object.keys(rest).length > 0) {
+    throw new TypeError(`PendingOp: unknown keys: ${Object.keys(rest).join(", ")}`);
+  }
+  if (typeof opId !== "string" || opId.trim().length === 0) {
+    throw new TypeError("PendingOp: opId must be a non-empty string");
+  }
+  if (typeof userId !== "string" || userId.trim().length === 0) {
+    throw new TypeError("PendingOp: userId must be a non-empty string");
+  }
+  if (typeof targetState !== "string" || targetState.trim().length === 0) {
+    throw new TypeError("PendingOp: targetState must be a non-empty string");
+  }
+  if (typeof previousState !== "string" || previousState.trim().length === 0) {
+    throw new TypeError("PendingOp: previousState must be a non-empty string");
+  }
+  if (typeof issuedAt !== "number" || !Number.isFinite(issuedAt) || issuedAt < 0 || !Number.isInteger(issuedAt)) {
+    throw new TypeError("PendingOp: issuedAt must be a finite non-negative integer");
+  }
+  if (timeoutId !== null) {
+    if (typeof timeoutId !== "number") {
+      throw new TypeError("PendingOp: timeoutId must be a number or null");
+    }
+    if (!Number.isFinite(timeoutId) || timeoutId < 0) {
+      throw new TypeError("PendingOp: timeoutId must be a finite non-negative number");
+    }
+  }
+  return /** @type {PendingOp} */ (data);
+}