refactor: extract readNativeHonkProof

Author: olehmisar

packages/contracts/sdk/NativeUltraHonkBackend.ts

@@ -1,11 +1,9 @@
 import type { ProofData } from "@aztec/bb.js";
 import type { CompiledCircuit } from "@noir-lang/noir_js";
-import { chunk } from "lodash-es";
 import { spawn } from "node:child_process";
 import fs from "node:fs";
 import path from "node:path";
-import { Hex } from "ox";
-import { assert } from "ts-essentials";
+import { readNativeHonkProof } from "./utils.js";
 
 export class NativeUltraHonkBackend {
   constructor(
@@ -62,22 +60,7 @@ export class NativeUltraHonkBackend {
           reject(new Error(`Process exited with code ${code}`));
           return;
         }
-
-        const proof = fs.readFileSync(path.join(proofOutputPath, "proof"));
-        const publicInputs = fs.readFileSync(
-          path.join(proofOutputPath, "public_inputs"),
-        );
-        assert(
-          publicInputs.length % 32 === 0,
-          "publicInputs length must be divisible by 32",
-        );
-        resolve({
-          proof,
-          // TODO: not sure if this publicInputs decoding is correct
-          publicInputs: chunk(Array.from(publicInputs), 32).map((x) =>
-            Hex.fromBytes(Uint8Array.from(x)),
-          ),
-        });
+        resolve(readNativeHonkProof(proofOutputPath));
       });
 
       bbProcess.on("error", (err) => {

packages/contracts/sdk/utils.ts

@@ -1,6 +1,10 @@
 import type { Fr } from "@aztec/aztec.js";
 import type { InputMap } from "@noir-lang/noir_js";
 import { ethers } from "ethers";
+import { chunk } from "lodash-es";
+import fs from "node:fs";
+import path from "node:path";
+import { Hex } from "ox";
 import { assert } from "ts-essentials";
 import type { NoirAndBackend } from "./sdk.js";
 
@@ -76,3 +80,21 @@ export async function prove(
   console.timeEnd(`${name} generateProof`);
   return { proof, witness, returnValue, publicInputs };
 }
+
+export function readNativeHonkProof(pathToProofDir: string) {
+  const proof = fs.readFileSync(path.join(pathToProofDir, "proof"));
+  const publicInputs = fs.readFileSync(
+    path.join(pathToProofDir, "public_inputs"),
+  );
+  assert(
+    publicInputs.length % 32 === 0,
+    "publicInputs length must be divisible by 32",
+  );
+  return {
+    proof,
+    // TODO: not sure if this publicInputs decoding is correct
+    publicInputs: chunk(Array.from(publicInputs), 32).map((x) =>
+      Hex.fromBytes(Uint8Array.from(x)),
+    ),
+  };
+}