diff --git a/core/ts/Poll.ts b/core/ts/Poll.ts
index bf18cac730..12e1a6677e 100644
--- a/core/ts/Poll.ts
+++ b/core/ts/Poll.ts
@@ -109,7 +109,7 @@ export class Poll implements IPoll {
 
   numBatchesTallied = 0;
 
-  totalSpentVoiceCredits = BigInt(0);
+  totalSpentVoiceCredits = 0n;
 
   // For coefficient and subsidy calculation
   subsidy: bigint[] = []; // size: M, M is number of vote options
@@ -163,9 +163,9 @@ export class Poll implements IPoll {
       hash5,
     );
 
-    this.tallyResult = new Array(this.maxValues.maxVoteOptions).fill(BigInt(0)) as bigint[];
-    this.perVOSpentVoiceCredits = new Array(this.maxValues.maxVoteOptions).fill(BigInt(0)) as bigint[];
-    this.subsidy = new Array(this.maxValues.maxVoteOptions).fill(BigInt(0)) as bigint[];
+    this.tallyResult = new Array(this.maxValues.maxVoteOptions).fill(0n) as bigint[];
+    this.perVOSpentVoiceCredits = new Array(this.maxValues.maxVoteOptions).fill(0n) as bigint[];
+    this.subsidy = new Array(this.maxValues.maxVoteOptions).fill(0n) as bigint[];
 
     // we put a blank state leaf to prevent a DoS attack
     this.emptyBallot = Ballot.genBlankBallot(this.maxValues.maxVoteOptions, treeDepths.voteOptionTreeDepth);
@@ -214,7 +214,7 @@ export class Poll implements IPoll {
       // If the state tree index in the command is invalid, do nothing
       if (
         stateLeafIndex >= BigInt(this.ballots.length) ||
-        stateLeafIndex < BigInt(1) ||
+        stateLeafIndex < 1n ||
         stateLeafIndex >= BigInt(this.stateTree?.nextIndex || -1)
       ) {
         throw new ProcessMessageError(ProcessMessageErrors.InvalidStateLeafIndex);
@@ -232,12 +232,12 @@ export class Poll implements IPoll {
       }
 
       // If the nonce is invalid, do nothing
-      if (command.nonce !== BigInt(`${ballot.nonce}`) + BigInt(1)) {
+      if (command.nonce !== BigInt(`${ballot.nonce}`) + 1n) {
         throw new ProcessMessageError(ProcessMessageErrors.InvalidNonce);
       }
 
       // If the vote option index is invalid, do nothing
-      if (command.voteOptionIndex < BigInt(0) || command.voteOptionIndex >= BigInt(this.maxValues.maxVoteOptions)) {
+      if (command.voteOptionIndex < 0n || command.voteOptionIndex >= BigInt(this.maxValues.maxVoteOptions)) {
         throw new ProcessMessageError(ProcessMessageErrors.InvalidVoteOptionIndex);
       }
 
@@ -257,7 +257,7 @@ export class Poll implements IPoll {
         BigInt(command.newVoteWeight) * BigInt(command.newVoteWeight);
 
       // If the remaining voice credits is insufficient, do nothing
-      if (voiceCreditsLeft < BigInt(0)) {
+      if (voiceCreditsLeft < 0n) {
         throw new ProcessMessageError(ProcessMessageErrors.InsufficientVoiceCredits);
       }
 
@@ -270,7 +270,7 @@ export class Poll implements IPoll {
       // Deep-copy the ballot and update its attributes
       const newBallot = ballot.copy();
       // increase the nonce
-      newBallot.nonce = BigInt(`${newBallot.nonce}`) + BigInt(1);
+      newBallot.nonce = BigInt(`${newBallot.nonce}`) + 1n;
       // we change the vote for this exact vote option
       newBallot.votes[voteOptionIndex] = command.newVoteWeight;
 
@@ -283,7 +283,7 @@ export class Poll implements IPoll {
       const originalBallotPathElements = this.ballotTree?.genMerklePath(Number(stateLeafIndex)).pathElements;
 
       // create a new quinary tree where we insert the votes of the origin (up until this message is processed) ballot
-      const vt = new IncrementalQuinTree(this.treeDepths.voteOptionTreeDepth, BigInt(0), STATE_TREE_ARITY, hash5);
+      const vt = new IncrementalQuinTree(this.treeDepths.voteOptionTreeDepth, 0n, STATE_TREE_ARITY, hash5);
       for (let i = 0; i < this.ballots[0].votes.length; i += 1) {
         vt.insert(ballot.votes[i]);
       }
@@ -317,7 +317,7 @@ export class Poll implements IPoll {
    * @param message - The message to top up the voice credit balance
    */
   topupMessage = (message: Message): void => {
-    assert(message.msgType === BigInt(2), "A Topup message must have msgType 2");
+    assert(message.msgType === 2n, "A Topup message must have msgType 2");
 
     message.data.forEach((d) => {
       assert(d < SNARK_FIELD_SIZE, "The message data is not in the correct range");
@@ -347,7 +347,7 @@ export class Poll implements IPoll {
    * @param encPubKey - The public key used to encrypt the message
    */
   publishMessage = (message: Message, encPubKey: PubKey): void => {
-    assert(message.msgType === BigInt(1), "A vote or key change message must have msgType 1");
+    assert(message.msgType === 1n, "A vote or key change message must have msgType 1");
     assert(
       encPubKey.rawPubKey[0] < SNARK_FIELD_SIZE && encPubKey.rawPubKey[1] < SNARK_FIELD_SIZE,
       "The public key is not in the correct range",
@@ -375,7 +375,7 @@ export class Poll implements IPoll {
     } catch (e) {
       // if there is an error we store an empty command
       const keyPair = new Keypair();
-      const command = new PCommand(BigInt(0), keyPair.pubKey, BigInt(0), BigInt(0), BigInt(0), BigInt(0), BigInt(0));
+      const command = new PCommand(0n, keyPair.pubKey, 0n, 0n, 0n, 0n, 0n);
       this.commands.push(command as ICommand);
     }
   };
@@ -449,7 +449,7 @@ export class Poll implements IPoll {
         }
       }
 
-      this.sbSalts[this.currentMessageBatchIndex] = BigInt(0);
+      this.sbSalts[this.currentMessageBatchIndex] = 0n;
     }
 
     // The starting index must be valid
@@ -495,7 +495,7 @@ export class Poll implements IPoll {
 
         // based on the message type we have to process it differently
         switch (message.msgType) {
-          case BigInt(1):
+          case 1n:
             try {
               // check if the command is valid
               const r = this.processMessage(message, encPubKey);
@@ -542,12 +542,12 @@ export class Poll implements IPoll {
               }
             }
             break;
-          case BigInt(2):
+          case 2n:
             try {
               // --------------------------------------
               // generate topup circuit inputs
-              const stateIndex = Number(message.data[0] >= BigInt(this.ballots.length) ? BigInt(0) : message.data[0]);
-              const amount = message.data[0] >= BigInt(this.ballots.length) ? BigInt(0) : message.data[1];
+              const stateIndex = Number(message.data[0] >= BigInt(this.ballots.length) ? 0n : message.data[0]);
+              const amount = message.data[0] >= BigInt(this.ballots.length) ? 0n : message.data[1];
 
               currentStateLeaves.unshift(this.stateLeaves[stateIndex].copy());
               currentStateLeavesPathElements.unshift(this.stateTree!.genMerklePath(stateIndex).pathElements);
@@ -597,7 +597,7 @@ export class Poll implements IPoll {
         currentVoteWeights.unshift(this.ballots[0].votes[0]);
 
         // create a new quinary tree and add an empty vote
-        const vt = new IncrementalQuinTree(this.treeDepths.voteOptionTreeDepth, BigInt(0), STATE_TREE_ARITY, hash5);
+        const vt = new IncrementalQuinTree(this.treeDepths.voteOptionTreeDepth, 0n, STATE_TREE_ARITY, hash5);
         vt.insert(this.ballots[0].votes[0]);
 
         // get the path elements for this empty vote weight leaf
@@ -728,9 +728,9 @@ export class Poll implements IPoll {
     /* eslint-disable no-bitwise */
     const packedVals =
       BigInt(this.maxValues.maxVoteOptions) +
-      (BigInt(this.maciStateRef.numSignUps) << BigInt(50)) +
-      (BigInt(index) << BigInt(100)) +
-      (BigInt(batchEndIndex) << BigInt(150));
+      (BigInt(this.maciStateRef.numSignUps) << 50n) +
+      (BigInt(index) << 100n) +
+      (BigInt(batchEndIndex) << 150n);
     /* eslint-enable no-bitwise */
 
     return stringifyBigInts({
@@ -800,8 +800,8 @@ export class Poll implements IPoll {
     const sbCommitment = hash3([stateRoot, ballotRoot, sbSalt]);
 
     const currentSubsidy = this.subsidy.map((x) => BigInt(x.toString()));
-    let currentSubsidyCommitment = BigInt(0);
-    let currentSubsidySalt = BigInt(0);
+    let currentSubsidyCommitment = 0n;
+    let currentSubsidySalt = 0n;
     let saltIndex = this.previousSubsidyIndexToString();
 
     if (this.rbi !== 0 || this.cbi !== 0) {
@@ -900,7 +900,7 @@ export class Poll implements IPoll {
    * @returns Returns the calculated coefficient.
    */
   private coefficientCalculation = (rowBallot: Ballot, colBallot: Ballot): bigint => {
-    let sum = BigInt(0);
+    let sum = 0n;
     for (let p = 0; p < this.maxValues.maxVoteOptions; p += 1) {
       sum += BigInt(rowBallot.votes[p].valueOf()) * colBallot.votes[p];
     }
@@ -965,10 +965,10 @@ export class Poll implements IPoll {
     const currentResultsRootSalt = batchStartIndex === 0 ? 0n : this.resultRootSalts[batchStartIndex - batchSize];
 
     const currentPerVOSpentVoiceCreditsRootSalt =
-      batchStartIndex === 0 ? BigInt(0) : this.preVOSpentVoiceCreditsRootSalts[batchStartIndex - batchSize];
+      batchStartIndex === 0 ? 0n : this.preVOSpentVoiceCreditsRootSalts[batchStartIndex - batchSize];
 
     const currentSpentVoiceCreditSubtotalSalt =
-      batchStartIndex === 0 ? BigInt(0) : this.spentVoiceCreditSubtotalSalts[batchStartIndex - batchSize];
+      batchStartIndex === 0 ? 0n : this.spentVoiceCreditSubtotalSalts[batchStartIndex - batchSize];
 
     // generate a commitment to the current results
     const currentResultsCommitment = genTreeCommitment(
@@ -998,7 +998,7 @@ export class Poll implements IPoll {
     // ])
     const currentTallyCommitment =
       batchStartIndex === 0
-        ? BigInt(0)
+        ? 0n
         : hash3([
             currentResultsCommitment,
             currentSpentVoiceCreditsCommitment,
@@ -1128,7 +1128,7 @@ export class Poll implements IPoll {
    * @returns Returns the hash of the total spent voice credits and a salt, computed as Poseidon([totalCredits, _salt]).
    */
   private genSpentVoiceCreditSubtotalCommitment = (salt: bigint, numBallotsToCount: number): bigint => {
-    let subtotal = BigInt(0);
+    let subtotal = 0n;
     for (let i = 0; i < numBallotsToCount; i += 1) {
       if (this.ballots.length <= i) {
         break;
diff --git a/core/ts/__tests__/MaciState.test.ts b/core/ts/__tests__/MaciState.test.ts
index 709e9f1fb6..c5f3090b5c 100644
--- a/core/ts/__tests__/MaciState.test.ts
+++ b/core/ts/__tests__/MaciState.test.ts
@@ -7,7 +7,14 @@ import { MaciState } from "../MaciState";
 import { STATE_TREE_DEPTH } from "../utils/constants";
 import { IJsonMaciState } from "../utils/types";
 
-import { coordinatorKeypair, duration, maxValues, messageBatchSize, treeDepths, voiceCreditBalance } from "./constants";
+import {
+  coordinatorKeypair,
+  duration,
+  maxValues,
+  messageBatchSize,
+  treeDepths,
+  voiceCreditBalance,
+} from "./utils/constants";
 
 describe("MaciState", function test() {
   this.timeout(100000);
@@ -34,15 +41,7 @@ describe("MaciState", function test() {
         messageBatchSize,
         coordinatorKeypair,
       );
-      const command = new PCommand(
-        BigInt(0),
-        userKeypair.pubKey,
-        BigInt(0),
-        BigInt(0),
-        BigInt(0),
-        BigInt(pollId),
-        BigInt(0),
-      );
+      const command = new PCommand(0n, userKeypair.pubKey, 0n, 0n, 0n, BigInt(pollId), 0n);
 
       const encKeypair = new Keypair();
       const signature = command.sign(encKeypair.privKey);
@@ -67,7 +66,7 @@ describe("MaciState", function test() {
 
       // modify user.voiceCreditBalance
       const m4 = m1.copy();
-      m4.stateLeaves[0].voiceCreditBalance = BigInt(m4.stateLeaves[0].voiceCreditBalance) + BigInt(1);
+      m4.stateLeaves[0].voiceCreditBalance = BigInt(m4.stateLeaves[0].voiceCreditBalance) + 1n;
       expect(m1.equals(m4)).not.to.eq(true);
 
       // modify poll.coordinatorKeypair
@@ -117,7 +116,7 @@ describe("MaciState", function test() {
 
       // modify poll.messages
       const m20 = m1.copy();
-      m20.polls[pollId].messages[0].data[0] = BigInt(m20.polls[pollId].messages[0].data[0]) + BigInt(1);
+      m20.polls[pollId].messages[0].data[0] = BigInt(m20.polls[pollId].messages[0].data[0]) + 1n;
       expect(m1.equals(m20)).not.to.eq(true);
 
       // modify poll.encPubKeys
diff --git a/core/ts/__tests__/Poll.test.ts b/core/ts/__tests__/Poll.test.ts
index 1cec8680e2..32b37c80e7 100644
--- a/core/ts/__tests__/Poll.test.ts
+++ b/core/ts/__tests__/Poll.test.ts
@@ -5,7 +5,14 @@ import { MaciState } from "../MaciState";
 import { Poll } from "../Poll";
 import { STATE_TREE_DEPTH } from "../utils/constants";
 
-import { coordinatorKeypair, duration, maxValues, messageBatchSize, treeDepths, voiceCreditBalance } from "./constants";
+import {
+  coordinatorKeypair,
+  duration,
+  maxValues,
+  messageBatchSize,
+  treeDepths,
+  voiceCreditBalance,
+} from "./utils/constants";
 
 describe("Poll", function test() {
   this.timeout(90000);
@@ -38,9 +45,9 @@ describe("Poll", function test() {
         // invalid state index as it is one more than the number of state leaves
         BigInt(user1StateIndex + 1),
         user1Keypair.pubKey,
-        BigInt(0),
-        BigInt(1),
-        BigInt(0),
+        0n,
+        1n,
+        0n,
         BigInt(pollId),
       );
 
@@ -57,14 +64,7 @@ describe("Poll", function test() {
     });
 
     it("should throw if a message has an invalid nonce", () => {
-      const command = new PCommand(
-        BigInt(user1StateIndex),
-        user1Keypair.pubKey,
-        BigInt(0),
-        BigInt(0),
-        BigInt(0),
-        BigInt(pollId),
-      );
+      const command = new PCommand(BigInt(user1StateIndex), user1Keypair.pubKey, 0n, 0n, 0n, BigInt(pollId));
 
       const signature = command.sign(user1Keypair.privKey);
 
@@ -80,16 +80,9 @@ describe("Poll", function test() {
     });
 
     it("should throw if a message has an invalid signature", () => {
-      const command = new PCommand(
-        BigInt(user1StateIndex),
-        user1Keypair.pubKey,
-        BigInt(0),
-        BigInt(0),
-        BigInt(0),
-        BigInt(pollId),
-      );
+      const command = new PCommand(BigInt(user1StateIndex), user1Keypair.pubKey, 0n, 0n, 0n, BigInt(pollId));
 
-      const signature = command.sign(new PrivKey(BigInt(0)));
+      const signature = command.sign(new PrivKey(0n));
       const ecdhKeypair = new Keypair();
       const sharedKey = Keypair.genEcdhSharedKey(ecdhKeypair.privKey, coordinatorKeypair.pubKey);
 
@@ -105,10 +98,10 @@ describe("Poll", function test() {
       const command = new PCommand(
         BigInt(user1StateIndex),
         user1Keypair.pubKey,
-        BigInt(0),
+        0n,
         // voice credits spent would be this value ** this value
         BigInt(Math.sqrt(Number.parseInt(voiceCreditBalance.toString(), 10)) + 1),
-        BigInt(1),
+        1n,
         BigInt(pollId),
       );
 
@@ -131,8 +124,8 @@ describe("Poll", function test() {
         user1Keypair.pubKey,
         BigInt(maxValues.maxVoteOptions),
         // voice credits spent would be this value ** this value
-        BigInt(1),
-        BigInt(1),
+        1n,
+        1n,
         BigInt(pollId),
       );
 
@@ -150,14 +143,7 @@ describe("Poll", function test() {
     });
 
     it("should throw if a message has an invalid vote option index (< 0)", () => {
-      const command = new PCommand(
-        BigInt(user1StateIndex),
-        user1Keypair.pubKey,
-        BigInt(-1),
-        BigInt(1),
-        BigInt(1),
-        BigInt(pollId),
-      );
+      const command = new PCommand(BigInt(user1StateIndex), user1Keypair.pubKey, -1n, 1n, 1n, BigInt(pollId));
 
       const signature = command.sign(user1Keypair.privKey);
 
@@ -173,14 +159,7 @@ describe("Poll", function test() {
     });
 
     it("should throw when passed a message that cannot be decrypted (wrong encPubKey)", () => {
-      const command = new PCommand(
-        BigInt(user1StateIndex),
-        user1Keypair.pubKey,
-        BigInt(0),
-        BigInt(1),
-        BigInt(1),
-        BigInt(pollId),
-      );
+      const command = new PCommand(BigInt(user1StateIndex), user1Keypair.pubKey, 0n, 1n, 1n, BigInt(pollId));
 
       const signature = command.sign(user1Keypair.privKey);
 
@@ -196,14 +175,7 @@ describe("Poll", function test() {
     });
 
     it("should throw when passed a corrupted message", () => {
-      const command = new PCommand(
-        BigInt(user1StateIndex),
-        user1Keypair.pubKey,
-        BigInt(0),
-        BigInt(1),
-        BigInt(1),
-        BigInt(pollId),
-      );
+      const command = new PCommand(BigInt(user1StateIndex), user1Keypair.pubKey, 0n, 1n, 1n, BigInt(pollId));
 
       const signature = command.sign(user1Keypair.privKey);
 
@@ -213,7 +185,7 @@ describe("Poll", function test() {
       const message = command.encrypt(signature, sharedKey);
       poll.publishMessage(message, ecdhKeypair.pubKey);
 
-      message.data[0] = BigInt(0);
+      message.data[0] = 0n;
 
       expect(() => {
         poll.processMessage(message, user1Keypair.pubKey);
@@ -242,14 +214,7 @@ describe("Poll", function test() {
     );
 
     it("should throw if this is the first batch and currentMessageBatchIndex is defined", () => {
-      const command = new PCommand(
-        BigInt(user1StateIndex),
-        user1Keypair.pubKey,
-        BigInt(0),
-        BigInt(1),
-        BigInt(0),
-        BigInt(pollId),
-      );
+      const command = new PCommand(BigInt(user1StateIndex), user1Keypair.pubKey, 0n, 1n, 0n, BigInt(pollId));
 
       const signature = command.sign(user1Keypair.privKey);
 
@@ -273,9 +238,9 @@ describe("Poll", function test() {
         // we only signed up one user so the state index is invalid
         BigInt(user1StateIndex + 1),
         user1Keypair.pubKey,
-        BigInt(0),
-        BigInt(1),
-        BigInt(0),
+        0n,
+        1n,
+        0n,
         BigInt(pollId),
       );
 
@@ -340,9 +305,9 @@ describe("Poll", function test() {
         // we only signed up one user so the state index is invalid
         BigInt(user1StateIndex + 1),
         user1Keypair.pubKey,
-        BigInt(0),
-        BigInt(1),
-        BigInt(0),
+        0n,
+        1n,
+        0n,
         BigInt(pollId),
       );
 
@@ -361,14 +326,7 @@ describe("Poll", function test() {
     });
 
     it("should return the correct state leaves and ballots", () => {
-      const command = new PCommand(
-        BigInt(user1StateIndex + 1),
-        user1Keypair.pubKey,
-        BigInt(0),
-        BigInt(1),
-        BigInt(0),
-        BigInt(pollId),
-      );
+      const command = new PCommand(BigInt(user1StateIndex + 1), user1Keypair.pubKey, 0n, 1n, 0n, BigInt(pollId));
 
       const signature = command.sign(user1Keypair.privKey);
 
@@ -388,14 +346,7 @@ describe("Poll", function test() {
     });
 
     it("should have processed all messages", () => {
-      const command = new PCommand(
-        BigInt(user1StateIndex + 1),
-        user1Keypair.pubKey,
-        BigInt(0),
-        BigInt(1),
-        BigInt(0),
-        BigInt(pollId),
-      );
+      const command = new PCommand(BigInt(user1StateIndex + 1), user1Keypair.pubKey, 0n, 1n, 0n, BigInt(pollId));
 
       const signature = command.sign(user1Keypair.privKey);
 
diff --git a/core/ts/__tests__/e2e.test.ts b/core/ts/__tests__/e2e.test.ts
index 02b897d476..398a1afd38 100644
--- a/core/ts/__tests__/e2e.test.ts
+++ b/core/ts/__tests__/e2e.test.ts
@@ -2,16 +2,22 @@ import { expect } from "chai";
 import { hash5, NOTHING_UP_MY_SLEEVE, IncrementalQuinTree, AccQueue } from "maci-crypto";
 import { PCommand, Keypair, StateLeaf, blankStateLeafHash } from "maci-domainobjs";
 
-import { coordinatorKeypair, duration, maxValues, messageBatchSize, treeDepths, voiceCreditBalance } from "./constants";
-import { TestHarness, calculateTotal } from "./utils";
-
-import { Poll } from "../Poll";
 import { MaciState } from "../MaciState";
-
+import { Poll } from "../Poll";
 import { STATE_TREE_DEPTH, STATE_TREE_ARITY, STATE_TREE_SUBDEPTH } from "../utils/constants";
 import { packProcessMessageSmallVals, unpackProcessMessageSmallVals } from "../utils/utils";
 
-describe("MaciState e2e", function test() {
+import {
+  coordinatorKeypair,
+  duration,
+  maxValues,
+  messageBatchSize,
+  treeDepths,
+  voiceCreditBalance,
+} from "./utils/constants";
+import { TestHarness, calculateTotal } from "./utils/utils";
+
+describe("MaciState/Poll e2e", function test() {
   this.timeout(300000);
 
   describe("key changes", () => {
@@ -22,12 +28,12 @@ describe("MaciState e2e", function test() {
     let pollId: number;
     let user1StateIndex: number;
     let user2StateIndex: number;
-    const user1VoteOptionIndex = BigInt(0);
-    const user2VoteOptionIndex = BigInt(1);
-    const user1VoteWeight = BigInt(9);
-    const user2VoteWeight = BigInt(3);
-    const user1NewVoteWeight = BigInt(5);
-    const user2NewVoteWeight = BigInt(7);
+    const user1VoteOptionIndex = 0n;
+    const user2VoteOptionIndex = 1n;
+    const user1VoteWeight = 9n;
+    const user2VoteWeight = 3n;
+    const user1NewVoteWeight = 5n;
+    const user2NewVoteWeight = 7n;
 
     describe("only user 1 changes key", () => {
       const maciState: MaciState = new MaciState(STATE_TREE_DEPTH);
@@ -61,7 +67,7 @@ describe("MaciState e2e", function test() {
           user1Keypair.pubKey,
           user1VoteOptionIndex,
           user1VoteWeight,
-          BigInt(1),
+          1n,
           BigInt(pollId),
         );
 
@@ -78,7 +84,7 @@ describe("MaciState e2e", function test() {
           user2Keypair.pubKey,
           user2VoteOptionIndex,
           user2VoteWeight,
-          BigInt(1),
+          1n,
           BigInt(pollId),
         );
 
@@ -98,7 +104,7 @@ describe("MaciState e2e", function test() {
           user1SecondKeypair.pubKey,
           user1VoteOptionIndex,
           user1NewVoteWeight,
-          BigInt(1),
+          1n,
           BigInt(pollId),
         );
 
@@ -160,7 +166,7 @@ describe("MaciState e2e", function test() {
           user1Keypair.pubKey,
           user1VoteOptionIndex,
           user1VoteWeight,
-          BigInt(1),
+          1n,
           BigInt(pollId),
         );
 
@@ -177,7 +183,7 @@ describe("MaciState e2e", function test() {
           user2Keypair.pubKey,
           user2VoteOptionIndex,
           user2VoteWeight,
-          BigInt(1),
+          1n,
           BigInt(pollId),
         );
 
@@ -197,7 +203,7 @@ describe("MaciState e2e", function test() {
           user1SecondKeypair.pubKey,
           user1VoteOptionIndex,
           user1NewVoteWeight,
-          BigInt(1),
+          1n,
           BigInt(pollId),
         );
 
@@ -217,7 +223,7 @@ describe("MaciState e2e", function test() {
           user2SecondKeypair.pubKey,
           user2VoteOptionIndex,
           user2NewVoteWeight,
-          BigInt(1),
+          1n,
           BigInt(pollId),
         );
 
@@ -275,7 +281,7 @@ describe("MaciState e2e", function test() {
           user1Keypair.pubKey,
           user1VoteOptionIndex,
           user1VoteWeight,
-          BigInt(1),
+          1n,
           BigInt(pollId),
         );
 
@@ -292,11 +298,11 @@ describe("MaciState e2e", function test() {
         const poll = maciState.polls[pollId];
         for (let i = 0; i < messageBatchSize - 1; i += 1) {
           const command = new PCommand(
-            BigInt(1),
+            1n,
             user1Keypair.pubKey,
             user1VoteOptionIndex,
             user1VoteWeight,
-            BigInt(2),
+            2n,
             BigInt(pollId),
           );
 
@@ -317,7 +323,7 @@ describe("MaciState e2e", function test() {
           user1SecondKeypair.pubKey,
           user1VoteOptionIndex,
           user1NewVoteWeight,
-          BigInt(1),
+          1n,
           BigInt(pollId),
         );
 
@@ -350,8 +356,8 @@ describe("MaciState e2e", function test() {
     let pollId: number;
     let poll: Poll;
     let msgTree: IncrementalQuinTree;
-    const voteWeight = BigInt(9);
-    const voteOptionIndex = BigInt(0);
+    const voteWeight = 9n;
+    const voteOptionIndex = 0n;
     let stateIndex: number;
     const userKeypair = new Keypair();
 
@@ -394,7 +400,7 @@ describe("MaciState e2e", function test() {
         userKeypair.pubKey,
         voteOptionIndex,
         voteWeight,
-        BigInt(1),
+        1n,
         BigInt(pollId),
       );
 
@@ -421,8 +427,8 @@ describe("MaciState e2e", function test() {
     });
 
     it("packProcessMessageSmallVals and unpackProcessMessageSmallVals", () => {
-      const maxVoteOptions = BigInt(1);
-      const numUsers = BigInt(2);
+      const maxVoteOptions = 1n;
+      const numUsers = 2n;
       const batchStartIndex = 5;
       const batchEndIndex = 10;
       const packedVals = packProcessMessageSmallVals(maxVoteOptions, numUsers, batchStartIndex, batchEndIndex);
@@ -462,7 +468,7 @@ describe("MaciState e2e", function test() {
     let maciState: MaciState;
     let pollId: number;
     let poll: Poll;
-    const voteWeight = BigInt(9);
+    const voteWeight = 9n;
 
     const users: Keypair[] = [];
 
@@ -496,7 +502,7 @@ describe("MaciState e2e", function test() {
           userKeypair.pubKey,
           BigInt(i), // vote option index
           voteWeight,
-          BigInt(1),
+          1n,
           BigInt(pollId),
         );
 
@@ -517,8 +523,8 @@ describe("MaciState e2e", function test() {
           BigInt(i + 1),
           userKeypair.pubKey,
           BigInt(i), // vote option index
-          voiceCreditBalance * BigInt(2), // invalid vote weight
-          BigInt(1),
+          voiceCreditBalance * 2n, // invalid vote weight
+          1n,
           BigInt(pollId),
         );
 
@@ -600,16 +606,16 @@ describe("MaciState e2e", function test() {
     let testHarness: TestHarness;
     let poll: Poll;
 
-    beforeEach(async () => {
+    beforeEach(() => {
       testHarness = new TestHarness();
 
       poll = testHarness.poll;
     });
 
-    it("processMessages() should process a valid message", async () => {
-      const voteOptionIndex = BigInt(0);
-      const voteWeight = BigInt(9);
-      const nonce = BigInt(1);
+    it("should process a valid message", () => {
+      const voteOptionIndex = 0n;
+      const voteWeight = 9n;
+      const nonce = 1n;
 
       const users = testHarness.createUsers(1);
       testHarness.vote(users[0], testHarness.getStateIndex(users[0]), voteOptionIndex, voteWeight, nonce);
@@ -620,14 +626,14 @@ describe("MaciState e2e", function test() {
       expect(messageLengthResult).to.eq(expectedNumVotes);
 
       const tallyResult = poll.tallyResult[0];
-      const expectedTallyResult = BigInt(9);
+      const expectedTallyResult = 9n;
       expect(tallyResult).to.eq(expectedTallyResult);
     });
 
-    it("processMessages() should not process messages twice", async () => {
-      const voteOptionIndex = BigInt(0);
-      const voteWeight = BigInt(9);
-      const nonce = BigInt(1);
+    it("should not process messages twice", () => {
+      const voteOptionIndex = 0n;
+      const voteWeight = 9n;
+      const nonce = 1n;
 
       const users = testHarness.createUsers(1);
       testHarness.vote(users[0], testHarness.getStateIndex(users[0]), voteOptionIndex, voteWeight, nonce);
@@ -644,24 +650,24 @@ describe("MaciState e2e", function test() {
       expect(messageLengthResult).to.eq(expectedNumVotes);
 
       const tallyResult = poll.tallyResult[0];
-      const expectedTallyResult = BigInt(9);
+      const expectedTallyResult = 9n;
       expect(tallyResult).to.eq(expectedTallyResult);
     });
 
-    it("processMessages() should not process a message with an incorrect nonce", async () => {
-      const voteOptionIndex = BigInt(0);
-      const voteWeight = BigInt(9);
+    it("should not process a message with an incorrect nonce", () => {
+      const voteOptionIndex = 0n;
+      const voteWeight = 9n;
 
       const users = testHarness.createUsers(5);
       // generate a bunch of invalid votes with nonces that are not 1
       let nonce: bigint;
-      for (let i = 0; i < users.length; i++) {
+      users.forEach((user) => {
         do {
           nonce = BigInt(Math.floor(Math.random() * 100) - 50);
-        } while (nonce === BigInt(1));
+        } while (nonce === 1n);
 
-        testHarness.vote(users[i], testHarness.getStateIndex(users[i]), voteOptionIndex, voteWeight, nonce);
-      }
+        testHarness.vote(user, testHarness.getStateIndex(user), voteOptionIndex, voteWeight, nonce);
+      });
 
       testHarness.finalizePoll();
 
@@ -670,7 +676,7 @@ describe("MaciState e2e", function test() {
       expect(messageLengthResult).to.eq(expectedNumVotes);
 
       const tallyResult = poll.tallyResult[0];
-      const expectedTallyResult = BigInt(0);
+      const expectedTallyResult = 0n;
       expect(tallyResult).to.eq(expectedTallyResult);
     });
 
@@ -678,21 +684,21 @@ describe("MaciState e2e", function test() {
     // the square of the vote weight. Since the maximum voice credit is 100 here,
     // the vote weight can only be a value between 1 and 10
     // (as these are the square roots of numbers up to 100).
-    it("processMessages() should not process a message with an incorrect vote weight", async () => {
-      const voteOptionIndex = BigInt(0);
-      const nonce = BigInt(1);
+    it("should not process a message with an incorrect vote weight", () => {
+      const voteOptionIndex = 0n;
+      const nonce = 1n;
 
       const users = testHarness.createUsers(5);
 
       // generate a bunch of invalid votes with vote weights that are not between 1 and 10
       let voteWeight: bigint;
-      for (let i = 0; i < users.length; i++) {
+      users.forEach((user) => {
         do {
           voteWeight = BigInt(Math.floor(Math.random() * 100) - 50);
-        } while (BigInt(1) <= voteWeight && voteWeight <= BigInt(10));
+        } while (voteWeight >= 1n && voteWeight <= 10n);
 
-        testHarness.vote(users[i], testHarness.getStateIndex(users[i]), voteOptionIndex, voteWeight, nonce);
-      }
+        testHarness.vote(user, testHarness.getStateIndex(user), voteOptionIndex, voteWeight, nonce);
+      });
 
       testHarness.finalizePoll();
 
@@ -701,22 +707,22 @@ describe("MaciState e2e", function test() {
       expect(messageLengthResult).to.eq(expectedNumVotes);
 
       const tallyResult = poll.tallyResult[0];
-      const expectedTallyResult = BigInt(0);
+      const expectedTallyResult = 0n;
       expect(tallyResult).to.eq(expectedTallyResult);
     });
 
-    it("processMessages() should not process a message with an incorrect state tree index", async () => {
-      const voteOptionIndex = BigInt(0);
-      const nonce = BigInt(1);
-      const voteWeight = BigInt(9);
+    it("should not process a message with an incorrect state tree index", () => {
+      const voteOptionIndex = 0n;
+      const nonce = 1n;
+      const voteWeight = 9n;
       const numVotes = 5;
 
       const users = testHarness.createUsers(5);
 
-      for (let i = 0; i < users.length; i++) {
+      users.forEach((user) => {
         // generate a bunch of invalid votes with incorrect state tree index
-        testHarness.vote(users[i], testHarness.getStateIndex(users[i]) + 1, voteOptionIndex, voteWeight, nonce);
-      }
+        testHarness.vote(user, testHarness.getStateIndex(user) + 1, voteOptionIndex, voteWeight, nonce);
+      });
 
       testHarness.finalizePoll();
 
@@ -725,14 +731,14 @@ describe("MaciState e2e", function test() {
       expect(messageLengthResult).to.eq(expectedNumVotes);
 
       const tallyResult = poll.tallyResult[0];
-      const expectedTallyResult = BigInt(0);
+      const expectedTallyResult = 0n;
       expect(tallyResult).to.eq(expectedTallyResult);
     });
 
-    it("processMessages() should not process a message with an incorrect signature", async () => {
-      const voteOptionIndex = BigInt(0);
-      const voteWeight = BigInt(9);
-      const nonce = BigInt(1);
+    it("should not process a message with an incorrect signature", () => {
+      const voteOptionIndex = 0n;
+      const voteWeight = 9n;
+      const nonce = 1n;
 
       const users = testHarness.createUsers(2);
 
@@ -768,14 +774,14 @@ describe("MaciState e2e", function test() {
       expect(messageLengthResult).to.eq(expectedNumVotes);
 
       const tallyResult = poll.tallyResult[0];
-      const expectedTallyResult = BigInt(0);
+      const expectedTallyResult = 0n;
       expect(tallyResult).to.eq(expectedTallyResult);
     });
 
-    it("processMessages() should not process a message with an invalid coordinator key", async () => {
-      const voteOptionIndex = BigInt(0);
-      const voteWeight = BigInt(9);
-      const nonce = BigInt(1);
+    it("should not process a message with an invalid coordinator key", () => {
+      const voteOptionIndex = 0n;
+      const voteWeight = 9n;
+      const nonce = 1n;
 
       const users = testHarness.createUsers(1);
 
@@ -797,7 +803,7 @@ describe("MaciState e2e", function test() {
       expect(messageLengthResult).to.eq(expectedNumVotes);
 
       const tallyResult = poll.tallyResult[0];
-      const expectedTallyResult = BigInt(0);
+      const expectedTallyResult = 0n;
       expect(tallyResult).to.eq(expectedTallyResult);
     });
   });
diff --git a/core/ts/__tests__/constants.ts b/core/ts/__tests__/utils/constants.ts
similarity index 88%
rename from core/ts/__tests__/constants.ts
rename to core/ts/__tests__/utils/constants.ts
index ce60e9d392..1e6c2215a2 100644
--- a/core/ts/__tests__/constants.ts
+++ b/core/ts/__tests__/utils/constants.ts
@@ -1,6 +1,6 @@
 import { Keypair } from "maci-domainobjs";
 
-export const voiceCreditBalance = BigInt(100);
+export const voiceCreditBalance = 100n;
 export const duration = 30;
 export const messageBatchSize = 25;
 export const coordinatorKeypair = new Keypair();
diff --git a/core/ts/__tests__/utils.ts b/core/ts/__tests__/utils/utils.ts
similarity index 93%
rename from core/ts/__tests__/utils.ts
rename to core/ts/__tests__/utils/utils.ts
index 75033dd23c..9911ccdc13 100644
--- a/core/ts/__tests__/utils.ts
+++ b/core/ts/__tests__/utils/utils.ts
@@ -1,29 +1,33 @@
 import { Signature } from "maci-crypto";
 import { PCommand, Message, Keypair, PubKey } from "maci-domainobjs";
 
-import { duration, maxValues, messageBatchSize, treeDepths, voiceCreditBalance } from "./constants";
-
-import { Poll } from "../Poll";
-import { MaciState } from "../MaciState";
+import { MaciState } from "../../MaciState";
+import { Poll } from "../../Poll";
+import { STATE_TREE_DEPTH } from "../../utils/constants";
 
-import { STATE_TREE_DEPTH } from "../utils/constants"
+import { duration, maxValues, messageBatchSize, treeDepths, voiceCreditBalance } from "./constants";
 
 /**
  * Calculates the total of a tally result
  * @param tallyResult - the tally result
  * @returns the total of the tally result
  */
-export const calculateTotal = (tallyResult: bigint[]): bigint => tallyResult.reduce((acc, v) => acc + v, BigInt(0));
+export const calculateTotal = (tallyResult: bigint[]): bigint => tallyResult.reduce((acc, v) => acc + v, 0n);
 
 /**
  * A test harness for the MACI contract.
  */
 export class TestHarness {
   maciState = new MaciState(STATE_TREE_DEPTH);
+
   coordinatorKeypair = new Keypair();
+
   poll: Poll;
+
   pollId: number;
+
   users: Keypair[] = [];
+
   stateIndices = new Map<Keypair, number>();
 
   /**
@@ -46,7 +50,7 @@ export class TestHarness {
    * @returns The keypairs of the newly created users.
    */
   createUsers = (numUsers: number): Keypair[] => {
-    for (let i = 0; i < numUsers; i++) {
+    for (let i = 0; i < numUsers; i += 1) {
       const user = new Keypair();
       this.users.push(user);
       const stateIndex = this.signup(user);
@@ -145,7 +149,5 @@ export class TestHarness {
    * @param user - The keypair of the user.
    * @returns The state index of the user.
    */
-  getStateIndex = (user: Keypair): number => {
-    return this.stateIndices.get(user)!;
-  };
-}
\ No newline at end of file
+  getStateIndex = (user: Keypair): number => this.stateIndices.get(user) || -1;
+}
diff --git a/core/ts/utils/utils.ts b/core/ts/utils/utils.ts
index cc6653eaaa..38374ef262 100644
--- a/core/ts/utils/utils.ts
+++ b/core/ts/utils/utils.ts
@@ -17,9 +17,9 @@ export const genProcessVkSig = (
   voteOptionTreeDepth: number,
   batchSize: number,
 ): bigint =>
-  (BigInt(batchSize) << BigInt(192)) +
-  (BigInt(stateTreeDepth) << BigInt(128)) +
-  (BigInt(messageTreeDepth) << BigInt(64)) +
+  (BigInt(batchSize) << 192n) +
+  (BigInt(stateTreeDepth) << 128n) +
+  (BigInt(messageTreeDepth) << 64n) +
   BigInt(voteOptionTreeDepth);
 
 /**
@@ -71,9 +71,9 @@ export const packProcessMessageSmallVals = (
   const packedVals =
     // Note: the << operator has lower precedence than +
     BigInt(`${maxVoteOptions}`) +
-    (BigInt(`${numUsers}`) << BigInt(50)) +
-    (BigInt(batchStartIndex) << BigInt(100)) +
-    (BigInt(batchEndIndex) << BigInt(150));
+    (BigInt(`${numUsers}`) << 50n) +
+    (BigInt(batchStartIndex) << 100n) +
+    (BigInt(batchEndIndex) << 150n);
 
   return packedVals;
 };
@@ -118,7 +118,7 @@ export const unpackProcessMessageSmallVals = (
  */
 export const packTallyVotesSmallVals = (batchStartIndex: number, batchSize: number, numSignUps: number): bigint => {
   // Note: the << operator has lower precedence than +
-  const packedVals = BigInt(batchStartIndex) / BigInt(batchSize) + (BigInt(numSignUps) << BigInt(50));
+  const packedVals = BigInt(batchStartIndex) / BigInt(batchSize) + (BigInt(numSignUps) << 50n);
 
   return packedVals;
 };
@@ -149,7 +149,7 @@ export const unpackTallyVotesSmallVals = (packedVals: bigint): { numSignUps: big
  */
 export const packSubsidySmallVals = (row: number, col: number, numSignUps: number): bigint => {
   // Note: the << operator has lower precedence than +
-  const packedVals = (BigInt(numSignUps) << BigInt(100)) + (BigInt(row) << BigInt(50)) + BigInt(col);
+  const packedVals = (BigInt(numSignUps) << 100n) + (BigInt(row) << 50n) + BigInt(col);
 
   return packedVals;
 };