Add dryRun to send opts (#21)

Author: hazim-j

README.md

@@ -4,6 +4,8 @@
 
 A simple JS library for building ERC-4337 UserOperations.
 
+> **🚀 Looking for access to hosted infrastructure to build your Smart Accounts? Check out [stackup.sh](https://www.stackup.sh/)!**
+
 # Usage
 
 See the `userop` documentation at [docs.stackup.sh](https://docs.stackup.sh/docs/useropjs).

package.json

@@ -1,6 +1,6 @@
 {
   "name": "userop",
-  "version": "0.1.5",
+  "version": "0.1.6",
   "description": "A simple JS library for building ERC-4337 UserOperations.",
   "types": "./dist/index.d.ts",
   "main": "./dist/index.js",

src/client.ts

@@ -6,6 +6,7 @@ import {
 } from "./types";
 import { EntryPoint, EntryPoint__factory } from "./typechain";
 import { OpToJSON } from "./utils";
+import { UserOperationMiddlewareCtx } from "./context";
 
 export class Client implements IClient {
   private provider: ethers.providers.JsonRpcProvider;
@@ -41,18 +42,29 @@ export class Client implements IClient {
     builder: IUserOperationBuilder,
     opts?: ISendUserOperationOpts
   ) {
+    const dryRun = Boolean(opts?.dryRun);
     const op = await this.buildUserOperation(builder);
     opts?.onBuild?.(op);
 
-    const userOpHash = (await this.provider.send("eth_sendUserOperation", [
-      OpToJSON(op),
-      this.entryPoint.address,
-    ])) as string;
+    const userOpHash = dryRun
+      ? new UserOperationMiddlewareCtx(
+          op,
+          this.entryPoint.address,
+          this.chainId
+        ).getUserOpHash()
+      : ((await this.provider.send("eth_sendUserOperation", [
+          OpToJSON(op),
+          this.entryPoint.address,
+        ])) as string);
     builder.resetOp();
 
     return {
       userOpHash,
       wait: async () => {
+        if (dryRun) {
+          return null;
+        }
+
         const end = Date.now() + this.waitTimeoutMs;
         const block = await this.provider.getBlock("latest");
         while (Date.now() < end) {

src/types.ts

@@ -89,6 +89,7 @@ export interface IClient {
 }
 
 export interface ISendUserOperationOpts {
+  dryRun?: boolean;
   onBuild?: (op: IUserOperation) => Promise<any> | any;
 }