chore: expose util func to convert field compressed string back to st…

…ring in aztec js (#9239) Resolves #9233
AztecProtocol · Oct 15, 2024 · ce7e687 · ce7e687
1 parent c857cd9
commit ce7e687
Show file tree

Hide file tree

Showing 5 changed files with 37 additions and 31 deletions.
diff --git a/yarn-project/aztec.js/src/index.ts b/yarn-project/aztec.js/src/index.ts
@@ -52,9 +52,11 @@ export {
   computeInnerAuthWitHashFromAction,
   computeInnerAuthWitHash,
   generatePublicKey,
+  readFieldCompressedString,
   waitForAccountSynch,
   waitForPXE,
 } from './utils/index.js';
+
 export { NoteSelector } from '@aztec/foundation/abi';
 
 export { createPXEClient, createCompatibleClient } from './rpc_clients/index.js';

diff --git a/yarn-project/aztec.js/src/utils/field_compressed_string.ts b/yarn-project/aztec.js/src/utils/field_compressed_string.ts
@@ -0,0 +1,27 @@
+import { Fr } from '@aztec/circuits.js';
+
+/**
+ * The representation of a FieldCompressedString in aztec.nr
+ */
+interface NoirFieldCompressedString {
+  /**
+   * The field value of the string
+   */
+  value: bigint;
+}
+/**
+ * This turns
+ * @param field - The field that contains the string
+ * @returns - the string that is decoded from the field
+ */
+export const readFieldCompressedString = (field: NoirFieldCompressedString): string => {
+  const vals: number[] = Array.from(new Fr(field.value).toBuffer());
+
+  let str = '';
+  for (let i = 0; i < vals.length; i++) {
+    if (vals[i] != 0) {
+      str += String.fromCharCode(Number(vals[i]));
+    }
+  }
+  return str;
+};
diff --git a/yarn-project/aztec.js/src/utils/index.ts b/yarn-project/aztec.js/src/utils/index.ts
@@ -6,3 +6,4 @@ export * from './authwit.js';
 export * from './pxe.js';
 export * from './account.js';
 export * from './anvil_test_watcher.js';
+export * from './field_compressed_string.js';
diff --git a/yarn-project/end-to-end/src/e2e_token_contract/reading_constants.test.ts b/yarn-project/end-to-end/src/e2e_token_contract/reading_constants.test.ts
@@ -1,19 +1,7 @@
-import { Fr } from '@aztec/circuits.js';
+import { readFieldCompressedString } from '@aztec/aztec.js';
 
 import { TokenContractTest } from './token_contract_test.js';
 
-const toString = ({ value }: { value: bigint }) => {
-  const vals: number[] = Array.from(new Fr(value).toBuffer());
-
-  let str = '';
-  for (let i = 0; i < vals.length; i++) {
-    if (vals[i] != 0) {
-      str += String.fromCharCode(Number(vals[i]));
-    }
-  }
-  return str;
-};
-
 describe('e2e_token_contract reading constants', () => {
   const t = new TokenContractTest('reading_constants');
   const { TOKEN_DECIMALS, TOKEN_NAME, TOKEN_SYMBOL } = TokenContractTest;
@@ -34,22 +22,22 @@ describe('e2e_token_contract reading constants', () => {
   });
 
   it('check name private', async () => {
-    const name = toString(await t.asset.methods.private_get_name().simulate());
+    const name = readFieldCompressedString(await t.asset.methods.private_get_name().simulate());
     expect(name).toBe(TOKEN_NAME);
   });
 
   it('check name public', async () => {
-    const name = toString(await t.asset.methods.public_get_name().simulate());
+    const name = readFieldCompressedString(await t.asset.methods.public_get_name().simulate());
     expect(name).toBe(TOKEN_NAME);
   });
 
   it('check symbol private', async () => {
-    const sym = toString(await t.asset.methods.private_get_symbol().simulate());
+    const sym = readFieldCompressedString(await t.asset.methods.private_get_symbol().simulate());
     expect(sym).toBe(TOKEN_SYMBOL);
   });
 
   it('check symbol public', async () => {
-    const sym = toString(await t.asset.methods.public_get_symbol().simulate());
+    const sym = readFieldCompressedString(await t.asset.methods.public_get_symbol().simulate());
     expect(sym).toBe(TOKEN_SYMBOL);
   });
 

diff --git a/yarn-project/end-to-end/src/spartan/transfer.test.ts b/yarn-project/end-to-end/src/spartan/transfer.test.ts
@@ -2,9 +2,9 @@ import { getSchnorrAccount } from '@aztec/accounts/schnorr';
 import {
   type AccountWalletWithSecretKey,
   type AztecAddress,
-  Fr,
   type PXE,
   createCompatibleClient,
+  readFieldCompressedString,
 } from '@aztec/aztec.js';
 import { createDebugLogger } from '@aztec/foundation/log';
 import { TokenContract } from '@aztec/noir-contracts.js';
@@ -18,18 +18,6 @@ if (!PXE_URL) {
   throw new Error('PXE_URL env variable must be set');
 }
 
-const toString = ({ value }: { value: bigint }) => {
-  const vals: number[] = Array.from(new Fr(value).toBuffer());
-
-  let str = '';
-  for (let i = 0; i < vals.length; i++) {
-    if (vals[i] != 0) {
-      str += String.fromCharCode(Number(vals[i]));
-    }
-  }
-  return str;
-};
-
 describe('token transfer test', () => {
   jest.setTimeout(10 * 60 * 2000); // 20 minutes
 
@@ -100,7 +88,7 @@ describe('token transfer test', () => {
   });
 
   it('can get info', async () => {
-    const name = toString(await tokenAdminWallet.methods.private_get_name().simulate());
+    const name = readFieldCompressedString(await tokenAdminWallet.methods.private_get_name().simulate());
     expect(name).toBe(TOKEN_NAME);
   });