fix: consolidate legacy adaptation. Add done adaptor

Agoric · Jul 25, 2020 · de99eb1 · de99eb1
1 parent d66b933
commit de99eb1
Showing 1 changed file with 24 additions and 11 deletions.
diff --git a/packages/notifier/src/notifier.js b/packages/notifier/src/notifier.js
@@ -57,6 +57,13 @@ import { producePromise } from '@agoric/produce-promise';
  * @property {Updater<T>} updater the (closely-held) notifier producer
  */
 
+/**
+ * Whether to enable deprecated legacy features to support legacy clients
+ * during the transition. TODO once all clients are updated to the new API,
+ * remove this flag and all code enabled by this flag.
+ */
+const supportLegacy = true;
+
 /**
  * Produces a pair of objects, which allow a service to produce a stream of
  * update promises.
@@ -78,8 +85,18 @@ export const produceNotifier = (...args) => {
   let currentUpdateCount = 1; // avoid falsy numbers
   let currentResponse;
 
-  if (args.length === 0) {
-    // Transitional kludge. TODO remove
+  const hasState = () => currentResponse !== undefined;
+
+  const final = () => currentUpdateCount === undefined;
+
+  const extraProperties = () =>
+    supportLegacy
+      ? {
+          updateHandle: currentUpdateCount,
+          done: final(),
+        }
+      : {};
+  if (supportLegacy && args.length === 0) {
     // To accommodate old clients, for now we treat no initial state
     // argument as if the argument defaults to undefined, as it used to.
     args = [undefined];
@@ -90,15 +107,11 @@ export const produceNotifier = (...args) => {
     currentResponse = harden({
       value: args[0],
       updateCount: currentUpdateCount,
-      updateHandle: currentUpdateCount, // deprecated. TODO remove
+      ...extraProperties(),
     });
   }
   // else start as !hasState() && !final()
 
-  const hasState = () => currentResponse !== undefined;
-
-  const final = () => currentUpdateCount === undefined;
-
   // NaN matches nothing
   function getUpdateSince(updateCount = NaN) {
     if (
@@ -123,7 +136,7 @@ export const produceNotifier = (...args) => {
     currentResponse = harden({
       value: state,
       updateCount: currentUpdateCount,
-      updateHandle: currentUpdateCount, // deprecated. TODO remove
+      ...extraProperties(),
     });
     nextPromiseKit.resolve(currentResponse);
     nextPromiseKit = producePromise();
@@ -138,8 +151,8 @@ export const produceNotifier = (...args) => {
     currentUpdateCount = undefined;
     currentResponse = harden({
       value: finalState,
-      updateCount: undefined,
-      updateHandle: undefined, // deprecated. TODO remove
+      updateCount: currentUpdateCount,
+      ...extraProperties(),
     });
     nextPromiseKit.resolve(currentResponse);
     nextPromiseKit = undefined;
@@ -162,8 +175,8 @@ export const produceNotifier = (...args) => {
   const updater = harden({
     updateState,
     fulfill,
-    resolve: fulfill, // deprecated. TODO remove
     reject,
+    ...(supportLegacy ? { resolve: fulfill } : {}),
   });
   return harden({ notifier, updater });
 };