diff --git a/.eslintrc.json b/.eslintrc.json
index 4b45ace9..ab7949c5 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -8,7 +8,7 @@
     "ecmaVersion": 8
   },
   "rules": {
-    "consistent-return": "off",
+    "consistent-return": "error",
     "func-name-matching": "off",
     "indent": ["error", 2, {
       "SwitchCase": 1,
diff --git a/bin/cli b/bin/cli
index 661b46c0..5d033b74 100755
--- a/bin/cli
+++ b/bin/cli
@@ -25,7 +25,7 @@ function CLI() {
 CLI.prototype.log = function log(json) {
   if (typeof json === 'string')
     return console.log.apply(console, arguments);
-  console.log(JSON.stringify(json, null, 2));
+  return console.log(JSON.stringify(json, null, 2));
 };
 
 CLI.prototype.getInfo = async function getInfo() {
@@ -491,81 +491,113 @@ CLI.prototype.handleWallet = async function handleWallet() {
 
   switch (this.argv.shift()) {
     case 'listen':
-      return await this.listenWallet();
+      await this.listenWallet();
+      break;
     case 'get':
-      return await this.getWallet();
+      await this.getWallet();
+      break;
     case 'master':
-      return await this.getMaster();
+      await this.getMaster();
+      break;
     case 'shared':
       if (this.argv[0] === 'add') {
         this.argv.shift();
-        return await this.addSharedKey();
+        await this.addSharedKey();
+        break;
       }
       if (this.argv[0] === 'remove') {
         this.argv.shift();
-        return await this.removeSharedKey();
+        await this.removeSharedKey();
+        break;
       }
       if (this.argv[0] === 'list')
         this.argv.shift();
-      return await this.getSharedKeys();
+      await this.getSharedKeys();
+      break;
     case 'balance':
-      return await this.getBalance();
+      await this.getBalance();
+      break;
     case 'history':
-      return await this.getWalletHistory();
+      await this.getWalletHistory();
+      break;
     case 'pending':
-      return await this.getWalletPending();
+      await this.getWalletPending();
+      break;
     case 'coins':
-      return await this.getWalletCoins();
+      await this.getWalletCoins();
+      break;
     case 'account':
       if (this.argv[0] === 'list') {
         this.argv.shift();
-        return await this.getAccounts();
+        await this.getAccounts();
+        break;
       }
       if (this.argv[0] === 'create') {
         this.argv.shift();
-        return await this.createAccount();
+        await this.createAccount();
+        break;
       }
       if (this.argv[0] === 'get')
         this.argv.shift();
-      return await this.getAccount();
+      await this.getAccount();
+      break;
     case 'address':
-      return await this.createAddress();
+      await this.createAddress();
+      break;
     case 'change':
-      return await this.createChange();
+      await this.createChange();
+      break;
     case 'nested':
-      return await this.createNested();
+      await this.createNested();
+      break;
     case 'retoken':
-      return await this.retoken();
+      await this.retoken();
+      break;
     case 'sign':
-      return await this.signTX();
+      await this.signTX();
+      break;
     case 'mktx':
-      return await this.createTX();
+      await this.createTX();
+      break;
     case 'send':
-      return await this.sendTX();
+      await this.sendTX();
+      break;
     case 'zap':
-      return await this.zapWallet();
+      await this.zapWallet();
+      break;
     case 'tx':
-      return await this.getDetails();
+      await this.getDetails();
+      break;
     case 'blocks':
-      return await this.getWalletBlocks();
+      await this.getWalletBlocks();
+      break;
     case 'block':
-      return await this.getWalletBlock();
+      await this.getWalletBlock();
+      break;
     case 'view':
-      return await this.viewTX();
+      await this.viewTX();
+      break;
     case 'import':
-      return await this.importKey();
+      await this.importKey();
+      break;
     case 'watch':
-      return await this.importAddress();
+      await this.importAddress();
+      break;
     case 'key':
-      return await this.getKey();
+      await this.getKey();
+      break;
     case 'dump':
-      return await this.getWIF();
+      await this.getWIF();
+      break;
     case 'lock':
-      return await this.lock();
+      await this.lock();
+      break;
     case 'unlock':
-      return await this.unlock();
+      await this.unlock();
+      break;
     case 'resend':
-      return await this.resendWallet();
+      await this.resendWallet();
+      break;
     default:
       this.log('Unrecognized command.');
       this.log('Commands:');
@@ -603,7 +635,7 @@ CLI.prototype.handleWallet = async function handleWallet() {
       this.log('Other Options:');
       this.log('  --passphrase [passphrase]: For signing and account creation.');
       this.log('  --account [account-name]: Account name.');
-      return;
+      break;
   }
 };
 
@@ -616,31 +648,44 @@ CLI.prototype.handleNode = async function handleNode() {
 
   switch (this.argv.shift()) {
     case 'info':
-      return await this.getInfo();
+      await this.getInfo();
+      break;
     case 'wallets':
-      return await this.getWallets();
+      await this.getWallets();
+      break;
     case 'mkwallet':
-      return await this.createWallet();
+      await this.createWallet();
+      break;
     case 'broadcast':
-      return await this.broadcast();
+      await this.broadcast();
+      break;
     case 'mempool':
-      return await this.getMempool();
+      await this.getMempool();
+      break;
     case 'tx':
-      return await this.getTX();
+      await this.getTX();
+      break;
     case 'coin':
-      return await this.getCoin();
+      await this.getCoin();
+      break;
     case 'block':
-      return await this.getBlock();
+      await this.getBlock();
+      break;
     case 'rescan':
-      return await this.rescan();
+      await this.rescan();
+      break;
     case 'reset':
-      return await this.reset();
+      await this.reset();
+      break;
     case 'resend':
-      return await this.resend();
+      await this.resend();
+      break;
     case 'backup':
-      return await this.backup();
+      await this.backup();
+      break;
     case 'rpc':
-      return await this.rpc();
+      await this.rpc();
+      break;
     default:
       this.log('Unrecognized command.');
       this.log('Commands:');
@@ -657,7 +702,7 @@ CLI.prototype.handleNode = async function handleNode() {
       this.log('  $ resend: Resend pending transactions.');
       this.log('  $ backup [path]: Backup the wallet db.');
       this.log('  $ rpc [command] [args]: Execute RPC command.');
-      return;
+      break;
   }
 };
 
@@ -668,29 +713,33 @@ CLI.prototype.open = async function open() {
       this.argv.shift();
       if (this.argv[0] === 'create') {
         this.argv[0] = 'mkwallet';
-        return await this.handleNode();
+        await this.handleNode();
+        break;
       }
-      return await this.handleWallet();
+      await this.handleWallet();
+      break;
     default:
-      return await this.handleNode();
+      await this.handleNode();
+      break;
   }
 };
 
 CLI.prototype.destroy = function destroy() {
   if (this.wallet)
     this.wallet.client.destroy();
+
   if (this.client)
     this.client.destroy();
+
   return Promise.resolve();
 };
 
-async function main() {
+(async () => {
   const cli = new CLI();
   await cli.open();
   await cli.destroy();
-}
-
-main().then(process.exit).catch((err) => {
-  console.error(err.stack + '');
-  return process.exit(1);
+  process.exit(0);
+})().catch((err) => {
+  console.error(err.stack);
+  process.exit(1);
 });
diff --git a/lib/bip70/paymentdetails.js b/lib/bip70/paymentdetails.js
index 10107e34..c665e423 100644
--- a/lib/bip70/paymentdetails.js
+++ b/lib/bip70/paymentdetails.js
@@ -151,7 +151,7 @@ PaymentDetails.prototype.getData = function getData(enc) {
     try {
       data = JSON.parse(data);
     } catch (e) {
-      return;
+      return null;
     }
     return data;
   }
diff --git a/lib/blockchain/chain.js b/lib/blockchain/chain.js
index 0ad2dc3d..91e0e3a9 100644
--- a/lib/blockchain/chain.js
+++ b/lib/blockchain/chain.js
@@ -953,8 +953,10 @@ Chain.prototype.setBestChain = async function setBestChain(entry, block, prev, f
 
     // In spv-mode, we reset the
     // chain and redownload the blocks.
-    if (this.options.spv)
-      return await this.reorganizeSPV(entry);
+    if (this.options.spv) {
+      await this.reorganizeSPV(entry);
+      return;
+    }
 
     await this.reorganize(entry);
   }
@@ -1138,8 +1140,10 @@ Chain.prototype._replay = async function _replay(block, silent) {
   if (!(await entry.isMainChain()))
     throw new Error('Cannot reset on alternate chain.');
 
-  if (entry.isGenesis())
-    return await this._reset(entry.hash, silent);
+  if (entry.isGenesis()) {
+    await this._reset(entry.hash, silent);
+    return;
+  }
 
   await this._reset(entry.prevBlock, silent);
 };
diff --git a/lib/btc/amount.js b/lib/btc/amount.js
index 49fa3e5b..a64e1e67 100644
--- a/lib/btc/amount.js
+++ b/lib/btc/amount.js
@@ -523,10 +523,8 @@ function pow10(exp) {
       return 10000000;
     case 8:
       return 100000000;
-    default:
-      assert(false, 'Exponent is too large.');
-      break;
   }
+  throw new Error('Exponent is too large.');
 }
 
 function modSafe(mod) {
@@ -549,10 +547,8 @@ function modSafe(mod) {
       return 4740991;
     case 100000000:
       return 54740991;
-    default:
-      assert(false, 'Exponent is too large.');
-      break;
   }
+  throw new Error('Exponent is too large.');
 }
 
 function divSafe(div) {
@@ -575,10 +571,8 @@ function divSafe(div) {
       return 900719925;
     case 100000000:
       return 90071992;
-    default:
-      assert(false, 'Exponent is too large.');
-      break;
   }
+  throw new Error('Exponent is too large.');
 }
 
 /*
diff --git a/lib/db/level.js b/lib/db/level.js
index a3010317..b033acd8 100644
--- a/lib/db/level.js
+++ b/lib/db/level.js
@@ -46,6 +46,8 @@ DB.prototype.batch = function batch(ops, options, callback) {
   }
 
   this.level.batch(ops, options, callback);
+
+  return undefined;
 };
 
 DB.prototype.iterator = function iterator(options) {
@@ -142,8 +144,10 @@ Iterator.prototype.seek = function seek(key) {
 };
 
 Iterator.prototype.end = function end(callback) {
-  if (this._end)
-    return callback(new Error('end() already called on iterator.'));
+  if (this._end) {
+    callback(new Error('end() already called on iterator.'));
+    return;
+  }
   this._end = true;
   this.iter.end(callback);
 };
diff --git a/lib/db/memdb.js b/lib/db/memdb.js
index 0c8a36b6..8c277eac 100644
--- a/lib/db/memdb.js
+++ b/lib/db/memdb.js
@@ -227,7 +227,7 @@ MemDB.prototype.batch = function _batch(ops, options, callback) {
   if (ops) {
     batch.ops = ops;
     batch.write(callback);
-    return;
+    return undefined;
   }
 
   return batch;
@@ -339,7 +339,7 @@ Batch.prototype.del = function del(key) {
 Batch.prototype.write = function write(callback) {
   if (this.written) {
     setImmediate(() => callback(new Error('Already written.')));
-    return;
+    return this;
   }
 
   for (const op of this.ops) {
@@ -352,7 +352,7 @@ Batch.prototype.write = function write(callback) {
         break;
       default:
         setImmediate(() => callback(new Error('Bad op.')));
-        return;
+        return this;
     }
   }
 
diff --git a/lib/http/base.js b/lib/http/base.js
index 011eae98..355aa435 100644
--- a/lib/http/base.js
+++ b/lib/http/base.js
@@ -218,19 +218,27 @@ HTTPBase.prototype.basicAuth = function basicAuth(options) {
   return async (req, res) => {
     const hdr = req.headers['authorization'];
 
-    if (!hdr)
-      return fail(res);
+    if (!hdr) {
+      fail(res);
+      return;
+    }
 
-    if (hdr.length > 1000)
-      return fail(res);
+    if (hdr.length > 1000) {
+      fail(res);
+      return;
+    }
 
     const parts = hdr.split(' ');
 
-    if (parts.length !== 2)
-      return fail(res);
+    if (parts.length !== 2) {
+      fail(res);
+      return;
+    }
 
-    if (parts[0] !== 'Basic')
-      return fail(res);
+    if (parts[0] !== 'Basic') {
+      fail(res);
+      return;
+    }
 
     const auth = Buffer.from(parts[1], 'base64').toString('utf8');
     const items = auth.split(':');
@@ -239,24 +247,32 @@ HTTPBase.prototype.basicAuth = function basicAuth(options) {
     const password = items.join(':');
 
     if (user) {
-      if (username.length > 255)
-        return fail(res);
+      if (username.length > 255) {
+        fail(res);
+        return;
+      }
 
       const raw = Buffer.from(username, 'utf8');
       const hash = digest.hash256(raw);
 
-      if (!ccmp(hash, user))
-        return fail(res);
+      if (!ccmp(hash, user)) {
+        fail(res);
+        return;
+      }
     }
 
-    if (password.length > 255)
-      return fail(res);
+    if (password.length > 255) {
+      fail(res);
+      return;
+    }
 
     const raw = Buffer.from(password, 'utf8');
     const hash = digest.hash256(raw);
 
-    if (!ccmp(hash, pass))
-      return fail(res);
+    if (!ccmp(hash, pass)) {
+      fail(res);
+      return;
+    }
 
     req.username = username;
   };
diff --git a/lib/net/pool.js b/lib/net/pool.js
index 7e258135..3db7ba69 100644
--- a/lib/net/pool.js
+++ b/lib/net/pool.js
@@ -2213,7 +2213,7 @@ Pool.prototype.handleBlock = async function handleBlock(peer, packet) {
     return;
   }
 
-  return await this.addBlock(peer, packet.block, flags);
+  await this.addBlock(peer, packet.block, flags);
 };
 
 /**
diff --git a/lib/net/socks.js b/lib/net/socks.js
index f6380029..2a21b5c7 100644
--- a/lib/net/socks.js
+++ b/lib/net/socks.js
@@ -662,7 +662,7 @@ Proxy.prototype.resume = function resume() {
 Proxy.prototype.destroy = function destroy() {
   if (!this.socket)
     return;
-  return this.socket.destroy();
+  this.socket.destroy();
 };
 
 /*
diff --git a/lib/node/logger.js b/lib/node/logger.js
index a0692ed3..747c8b24 100644
--- a/lib/node/logger.js
+++ b/lib/node/logger.js
@@ -394,8 +394,10 @@ Logger.prototype.error = function error(...args) {
 
   const err = args[0];
 
-  if (err instanceof Error)
-    return this.logError(Logger.levels.ERROR, null, err);
+  if (err instanceof Error) {
+    this.logError(Logger.levels.ERROR, null, err);
+    return;
+  }
 
   this.log(Logger.levels.ERROR, null, args);
 };
@@ -412,8 +414,10 @@ Logger.prototype.warning = function warning(...args) {
 
   const err = args[0];
 
-  if (err instanceof Error)
-    return this.logError(Logger.levels.WARNING, null, err);
+  if (err instanceof Error) {
+    this.logError(Logger.levels.WARNING, null, err);
+    return;
+  }
 
   this.log(Logger.levels.WARNING, null, args);
 };
@@ -430,8 +434,10 @@ Logger.prototype.info = function info(...args) {
 
   const err = args[0];
 
-  if (err instanceof Error)
-    return this.logError(Logger.levels.INFO, null, err);
+  if (err instanceof Error) {
+    this.logError(Logger.levels.INFO, null, err);
+    return;
+  }
 
   this.log(Logger.levels.INFO, null, args);
 };
@@ -448,8 +454,10 @@ Logger.prototype.debug = function debug(...args) {
 
   const err = args[0];
 
-  if (err instanceof Error)
-    return this.logError(Logger.levels.DEBUG, null, err);
+  if (err instanceof Error) {
+    this.logError(Logger.levels.DEBUG, null, err);
+    return;
+  }
 
   this.log(Logger.levels.DEBUG, null, args);
 };
@@ -466,8 +474,10 @@ Logger.prototype.spam = function spam(...args) {
 
   const err = args[0];
 
-  if (err instanceof Error)
-    return this.logError(Logger.levels.SPAM, null, err);
+  if (err instanceof Error) {
+    this.logError(Logger.levels.SPAM, null, err);
+    return;
+  }
 
   this.log(Logger.levels.SPAM, null, args);
 };
@@ -521,7 +531,7 @@ Logger.prototype.writeConsole = function writeConsole(level, module, args) {
   assert(name, 'Invalid log level.');
 
   if (!this.console)
-    return;
+    return false;
 
   if (!process.stdout) {
     let msg = `[${name}] `;
@@ -537,13 +547,17 @@ Logger.prototype.writeConsole = function writeConsole(level, module, args) {
 
     msg += util.format(args, false);
 
-    return level === Logger.levels.ERROR
-      ? console.error(msg)
-      : console.log(msg);
+    if (level === Logger.levels.ERROR) {
+      console.error(msg);
+      return true;
+    }
+
+    console.log(msg);
+
+    return true;
   }
 
   let msg;
-
   if (this.colors) {
     const color = Logger.styles[level];
     assert(color);
@@ -707,8 +721,10 @@ LoggerContext.prototype.error = function error(...args) {
 
   const err = args[0];
 
-  if (err instanceof Error)
-    return this.logError(Logger.levels.ERROR, err);
+  if (err instanceof Error) {
+    this.logError(Logger.levels.ERROR, err);
+    return;
+  }
 
   this.log(Logger.levels.ERROR, args);
 };
@@ -725,8 +741,10 @@ LoggerContext.prototype.warning = function warning(...args) {
 
   const err = args[0];
 
-  if (err instanceof Error)
-    return this.logError(Logger.levels.WARNING, err);
+  if (err instanceof Error) {
+    this.logError(Logger.levels.WARNING, err);
+    return;
+  }
 
   this.log(Logger.levels.WARNING, args);
 };
@@ -743,8 +761,10 @@ LoggerContext.prototype.info = function info(...args) {
 
   const err = args[0];
 
-  if (err instanceof Error)
-    return this.logError(Logger.levels.INFO, err);
+  if (err instanceof Error) {
+    this.logError(Logger.levels.INFO, err);
+    return;
+  }
 
   this.log(Logger.levels.INFO, args);
 };
@@ -761,8 +781,10 @@ LoggerContext.prototype.debug = function debug(...args) {
 
   const err = args[0];
 
-  if (err instanceof Error)
-    return this.logError(Logger.levels.DEBUG, err);
+  if (err instanceof Error) {
+    this.logError(Logger.levels.DEBUG, err);
+    return;
+  }
 
   this.log(Logger.levels.DEBUG, args);
 };
@@ -779,8 +801,10 @@ LoggerContext.prototype.spam = function spam(...args) {
 
   const err = args[0];
 
-  if (err instanceof Error)
-    return this.logError(Logger.levels.SPAM, err);
+  if (err instanceof Error) {
+    this.logError(Logger.levels.SPAM, err);
+    return;
+  }
 
   this.log(Logger.levels.SPAM, args);
 };
diff --git a/lib/primitives/tx.js b/lib/primitives/tx.js
index 5f175d08..188899a0 100644
--- a/lib/primitives/tx.js
+++ b/lib/primitives/tx.js
@@ -431,7 +431,7 @@ TX.prototype.signatureHash = function signatureHash(index, prev, value, type, ve
   if (version === 1)
     return this.signatureHashV1(index, prev, value, type);
 
-  assert(false, 'Unknown sighash version.');
+  throw new Error('Unknown sighash version.');
 };
 
 /**
@@ -811,10 +811,12 @@ TX.prototype.checkAsync = async function checkAsync(view, flags, pool) {
   if (this.isCoinbase())
     return;
 
-  if (!pool)
-    return this.check(view, flags);
+  if (!pool) {
+    this.check(view, flags);
+    return;
+  }
 
-  return await pool.check(this, view, flags);
+  await pool.check(this, view, flags);
 };
 
 /**
@@ -833,10 +835,12 @@ TX.prototype.checkInputAsync = async function checkInputAsync(index, coin, flags
   assert(input, 'Input does not exist.');
   assert(coin, 'No coin passed.');
 
-  if (!pool)
-    return this.checkInput(index, coin, flags);
+  if (!pool) {
+    this.checkInput(index, coin, flags);
+    return;
+  }
 
-  return await pool.checkInput(this, index, coin, flags);
+  await pool.checkInput(this, index, coin, flags);
 };
 
 /**
diff --git a/lib/protocol/network.js b/lib/protocol/network.js
index fd973947..16d2144a 100644
--- a/lib/protocol/network.js
+++ b/lib/protocol/network.js
@@ -199,7 +199,7 @@ Network.get = function get(type) {
   if (typeof type === 'string')
     return Network.create(type);
 
-  assert(false, 'Unknown network.');
+  throw new Error('Unknown network.');
 };
 
 /**
diff --git a/lib/script/opcode.js b/lib/script/opcode.js
index 8eae5dc5..ed4a9881 100644
--- a/lib/script/opcode.js
+++ b/lib/script/opcode.js
@@ -396,7 +396,7 @@ Opcode.from = function from(data) {
   if (BN.isBN(data))
     return Opcode.fromNumber(data);
 
-  assert(false, 'Bad data for opcode.');
+  throw new Error('Bad data for opcode.');
 };
 
 /**
diff --git a/lib/script/scriptnum.js b/lib/script/scriptnum.js
index 94c4f347..2498d4cc 100644
--- a/lib/script/scriptnum.js
+++ b/lib/script/scriptnum.js
@@ -154,7 +154,7 @@ ScriptNum.prototype.toString = function toString(base) {
     return str;
   }
 
-  assert(false, `Base ${base} not supported.`);
+  throw new Error(`Base ${base} not supported.`);
 };
 
 ScriptNum.prototype.toJSON = function toJSON() {
@@ -237,7 +237,7 @@ ScriptNum.prototype.fromString = function fromString(str, base) {
     return this;
   }
 
-  assert(false, `Base ${base} not supported.`);
+  throw new Error(`Base ${base} not supported.`);
 };
 
 ScriptNum.fromString = function fromString(str, base) {
diff --git a/lib/utils/ip.js b/lib/utils/ip.js
index 59b124f4..6ca0f751 100644
--- a/lib/utils/ip.js
+++ b/lib/utils/ip.js
@@ -484,7 +484,7 @@ IP.getType = function getType(raw) {
   if (IP.isOnion(raw))
     return IP.types.ONION;
 
-  assert(false, 'Unknown type.');
+  throw new Error('Unknown type.');
 };
 
 /**
diff --git a/lib/utils/staticwriter.js b/lib/utils/staticwriter.js
index 2cd37156..83377a5e 100644
--- a/lib/utils/staticwriter.js
+++ b/lib/utils/staticwriter.js
@@ -369,7 +369,8 @@ StaticWriter.prototype.writeString = function writeString(value, enc) {
 StaticWriter.prototype.writeHash = function writeHash(value) {
   if (typeof value !== 'string') {
     assert(value.length === 32);
-    return this.writeBytes(value);
+    this.writeBytes(value);
+    return;
   }
   assert(value.length === 64);
   this.data.write(value, this.written, 'hex');
diff --git a/lib/utils/util.js b/lib/utils/util.js
index bc6f5b4a..19e2cac5 100644
--- a/lib/utils/util.js
+++ b/lib/utils/util.js
@@ -551,7 +551,7 @@ util.pad8 = function pad8(num) {
       return num;
   }
 
-  assert(false);
+  throw new Error('Number too big.');
 };
 
 /**
@@ -590,7 +590,7 @@ util.pad32 = function pad32(num) {
       return num;
   }
 
-  assert(false);
+  throw new Error('Number too big.');
 };
 
 /**
@@ -613,7 +613,7 @@ util.hex8 = function hex8(num) {
       return num;
   }
 
-  assert(false);
+  throw new Error('Number too big.');
 };
 
 /**
@@ -648,7 +648,7 @@ util.hex32 = function hex32(num) {
       return num;
   }
 
-  assert(false);
+  throw new Error('Number too big.');
 };
 
 /**
diff --git a/lib/utils/writer.js b/lib/utils/writer.js
index e8d9c0f6..fe37a500 100644
--- a/lib/utils/writer.js
+++ b/lib/utils/writer.js
@@ -466,7 +466,8 @@ BufferWriter.prototype.writeString = function writeString(value, enc) {
 BufferWriter.prototype.writeHash = function writeHash(value) {
   if (typeof value !== 'string') {
     assert(value.length === 32);
-    return this.writeBytes(value);
+    this.writeBytes(value);
+    return;
   }
   assert(value.length === 64);
   this.writeString(value, 'hex');
diff --git a/lib/wallet/account.js b/lib/wallet/account.js
index 82b54fab..70e492c4 100644
--- a/lib/wallet/account.js
+++ b/lib/wallet/account.js
@@ -519,7 +519,7 @@ Account.prototype.derivePath = function derivePath(path, master) {
       return null;
     }
     default: {
-      assert(false, 'Bad key type.');
+      throw new Error('Bad key type.');
     }
   }
 };
diff --git a/lib/wallet/client.js b/lib/wallet/client.js
index 38256902..04c74c54 100644
--- a/lib/wallet/client.js
+++ b/lib/wallet/client.js
@@ -100,7 +100,8 @@ WalletClient.prototype._open = async function _open() {
       block = parseBlock(entry, txs);
     } catch (e) {
       this.emit('error', e);
-      return cb();
+      cb();
+      return;
     }
 
     this.fire('block rescan', block.entry, block.txs).then(cb, cb);
diff --git a/migrate/chaindb1to2.js b/migrate/chaindb1to2.js
index 2f1e1560..57babdd7 100644
--- a/migrate/chaindb1to2.js
+++ b/migrate/chaindb1to2.js
@@ -197,7 +197,7 @@ async function reserializeUndo() {
 function write(data, str, off) {
   if (Buffer.isBuffer(str))
     return str.copy(data, off);
-  data.write(str, off, 'hex');
+  return data.write(str, off, 'hex');
 }
 
 function pair(prefix, hash) {
diff --git a/migrate/chaindb2to3.js b/migrate/chaindb2to3.js
index 9e830b74..98164e23 100644
--- a/migrate/chaindb2to3.js
+++ b/migrate/chaindb2to3.js
@@ -541,7 +541,7 @@ function entryToRaw(entry, main) {
 function write(data, str, off) {
   if (Buffer.isBuffer(str))
     return str.copy(data, off);
-  data.write(str, off, 'hex');
+  return data.write(str, off, 'hex');
 }
 
 function pair(prefix, hash) {
diff --git a/migrate/coins-old.js b/migrate/coins-old.js
index a5b436c9..5d8cb713 100644
--- a/migrate/coins-old.js
+++ b/migrate/coins-old.js
@@ -4,6 +4,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+/* eslint-disable */
+
 'use strict';
 
 const assert = require('assert');
diff --git a/migrate/coins/coins.js b/migrate/coins/coins.js
index c4c74c72..edacce24 100644
--- a/migrate/coins/coins.js
+++ b/migrate/coins/coins.js
@@ -4,6 +4,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+/* eslint-disable */
+
 'use strict';
 
 const assert = require('assert');
diff --git a/migrate/coins/coinview.js b/migrate/coins/coinview.js
index 659fe93b..6f70250b 100644
--- a/migrate/coins/coinview.js
+++ b/migrate/coins/coinview.js
@@ -4,6 +4,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+/* eslint-disable */
+
 'use strict';
 
 const assert = require('assert');
diff --git a/migrate/coins/compress.js b/migrate/coins/compress.js
index d890455a..455780c1 100644
--- a/migrate/coins/compress.js
+++ b/migrate/coins/compress.js
@@ -4,6 +4,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+/* eslint-disable */
+
 'use strict';
 
 /**
diff --git a/migrate/coins/undocoins.js b/migrate/coins/undocoins.js
index b1e6e607..0e9acedd 100644
--- a/migrate/coins/undocoins.js
+++ b/migrate/coins/undocoins.js
@@ -4,6 +4,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+/* eslint-disable */
+
 'use strict';
 
 const assert = require('assert');
diff --git a/migrate/coinview-old.js b/migrate/coinview-old.js
index e9880d0b..4d363921 100644
--- a/migrate/coinview-old.js
+++ b/migrate/coinview-old.js
@@ -4,6 +4,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+/* eslint-disable */
+
 'use strict';
 
 const assert = require('assert');
diff --git a/migrate/ensure-tip-index.js b/migrate/ensure-tip-index.js
index 2fa074ee..200322dc 100644
--- a/migrate/ensure-tip-index.js
+++ b/migrate/ensure-tip-index.js
@@ -121,7 +121,7 @@ async function indexTips() {
 function write(data, str, off) {
   if (Buffer.isBuffer(str))
     return str.copy(data, off);
-  data.write(str, off, 'hex');
+  return data.write(str, off, 'hex');
 }
 
 function pair(prefix, hash) {
diff --git a/scripts/fuzz.js b/scripts/fuzz.js
index 2a3b3288..6a4ce540 100644
--- a/scripts/fuzz.js
+++ b/scripts/fuzz.js
@@ -1,6 +1,5 @@
 'use strict';
 
-const assert = require('assert');
 const util = require('../lib/utils/util');
 const Script = require('../lib/script/script');
 const Stack = require('../lib/script/stack');
@@ -173,7 +172,7 @@ function randomRedeem() {
     case 4:
       return randomProgram();
   }
-  assert(false);
+  throw new Error();
 }
 
 function randomScript() {
@@ -193,7 +192,7 @@ function randomScript() {
     case 6:
       return randomProgram();
   }
-  assert(false);
+  throw new Error();
 }
 
 function randomPubkeyContext() {
@@ -269,7 +268,7 @@ function randomContext() {
     case 5:
       return randomWitnessNestedContext();
   }
-  assert(false);
+  throw new Error();
 }
 
 function fuzzSimple(flags) {
@@ -434,11 +433,14 @@ function main() {
 
   switch (process.argv[2]) {
     case 'simple':
-      return fuzzSimple(flags);
+      fuzzSimple(flags);
+      break;
     case 'verify':
-      return fuzzVerify(flags);
+      fuzzVerify(flags);
+      break;
     case 'less':
-      return fuzzLess(flags);
+      fuzzLess(flags);
+      break;
     default:
       util.log('Please select a mode:');
       util.log('simple, verify, less');