feat: add contract event effect

effects/contracts/events.ts

@@ -0,0 +1,28 @@
+import * as $ from "../../deps/scale.ts"
+import * as Z from "../../deps/zones.ts"
+import { ContractMetadata, DeriveCodec } from "../../frame_metadata/mod.ts"
+import { ExtrinsicEvent } from "../events.ts"
+
+export function events(
+  contractMetadata: Z.$<ContractMetadata>,
+  events: Z.$<ExtrinsicEvent[]>,
+) {
+  const $events = Z.ls(contractMetadata).next(([contractMetadata]) => {
+    return $.taggedUnion(
+      "type",
+      contractMetadata.V3.spec.events
+        .map((e) => [
+          e.label,
+          [
+            "value",
+            $.tuple(...e.args.map((a) => DeriveCodec(contractMetadata.V3.types)(a.type.type))),
+          ],
+        ]),
+    )
+  })
+  return Z.ls(events, $events).next(([events, $events]) => {
+    return events
+      .filter((e) => e.event?.type === "Contracts" && e.event?.value?.type === "ContractEmitted")
+      .map((e) => $events.decode(e.event?.value.data))
+  })
+}

effects/contracts/mod.ts

@@ -1,2 +1,3 @@
 export * from "./call.ts"
+export * from "./events.ts"
 export * from "./instantiate.ts"

effects/events.ts

@@ -24,10 +24,7 @@ export function events<Extrinsic extends SignedExtrinsic, FinalizedHash extends
     }, k1_)
   const events = entryRead(client)("System", "Events", [], finalizedHash)
     .access("value")
-    .as<{
-      event?: Record<string, any>
-      phase: { value: number }
-    }[]>()
+    .as<ExtrinsicEvent[]>()
   return Z
     .ls(idx, events)
     .next(([idx, events]) => {
@@ -36,3 +33,8 @@ export function events<Extrinsic extends SignedExtrinsic, FinalizedHash extends
       })
     }, k2_)
 }
+
+export type ExtrinsicEvent = {
+  event?: Record<string, any>
+  phase: { value: number }
+}

examples/smart_contract.ts

@@ -68,23 +68,11 @@ const contractAddress = U.throwIfError(
 )
 
 class Contract<Client extends C.Z.Effect<C.rpc.Client>> {
-  readonly $events
-
   constructor(
     readonly client: Client,
     readonly contractMetadata: C.M.ContractMetadata,
     readonly contractAddress: Uint8Array,
-  ) {
-    const deriveCodec = C.M.DeriveCodec(contractMetadata.V3.types)
-    this.$events = C.$.taggedUnion(
-      "type",
-      contractMetadata.V3.spec.events
-        .map((e) => [
-          e.label,
-          ["value", C.$.tuple(...e.args.map((a) => deriveCodec(a.type.type)))],
-        ]),
-    )
-  }
+  ) {}
 
   call<Args extends any[]>(
     sender: C.MultiAddress,
@@ -126,15 +114,9 @@ class Contract<Client extends C.Z.Effect<C.rpc.Client>> {
         return
       }
     )
-    return C.Z.ls(finalizedIn, C.events(tx, finalizedIn))
-      .next(([finalizedIn, events]) => {
-        const contractEvents: any[] = events
-          .filter((e) =>
-            e.event?.type === "Contracts" && e.event?.value?.type === "ContractEmitted"
-          )
-          .map((e) => this.$events.decode(e.event?.value.data))
-        return [finalizedIn, events, contractEvents]
-      })
+    const events = C.events(tx, finalizedIn)
+    const contractEvents = C.contracts.events(this.contractMetadata, events)
+    return C.Z.ls(finalizedIn, events, contractEvents)
   }
 
   // TODO: codegen each contract message as a method