diff --git a/lib/api/api-upgrade.js b/lib/api/api-upgrade.js
index 019fe1efa2d..7effcf21049 100644
--- a/lib/api/api-upgrade.js
+++ b/lib/api/api-upgrade.js
@@ -50,9 +50,9 @@ class UpgradeHandler extends AsyncResource {
   }
 
   onUpgrade (statusCode, rawHeaders, socket) {
-    const { callback, opaque, context } = this
+    assert(statusCode === 101)
 
-    assert.strictEqual(statusCode, 101)
+    const { callback, opaque, context } = this
 
     removeSignal(this)
 
diff --git a/lib/core/connect.js b/lib/core/connect.js
index e40fb90d81c..50578534ae8 100644
--- a/lib/core/connect.js
+++ b/lib/core/connect.js
@@ -92,10 +92,10 @@ function buildConnector ({ allowH2, maxCachedSessions, socketPath, timeout, sess
       servername = servername || options.servername || util.getServerName(host) || null
 
       const sessionKey = servername || hostname
-      const session = customSession || sessionCache.get(sessionKey) || null
-
       assert(sessionKey)
 
+      const session = customSession || sessionCache.get(sessionKey) || null
+
       socket = tls.connect({
         highWaterMark: 16384, // TLS in node can't have bigger HWM anyway...
         ...options,
diff --git a/lib/core/util.js b/lib/core/util.js
index 00f8a9b200a..9ee7ec23c52 100644
--- a/lib/core/util.js
+++ b/lib/core/util.js
@@ -233,7 +233,7 @@ function getServerName (host) {
     return null
   }
 
-  assert.strictEqual(typeof host, 'string')
+  assert(typeof host === 'string')
 
   const servername = getHostname(host)
   if (net.isIP(servername)) {
diff --git a/lib/dispatcher/client-h1.js b/lib/dispatcher/client-h1.js
index db5fd6c3746..4a26f641283 100644
--- a/lib/dispatcher/client-h1.js
+++ b/lib/dispatcher/client-h1.js
@@ -85,35 +85,35 @@ async function lazyllhttp () {
         return 0
       },
       wasm_on_status: (p, at, len) => {
-        assert.strictEqual(currentParser.ptr, p)
+        assert(currentParser.ptr === p)
         const start = at - currentBufferPtr + currentBufferRef.byteOffset
         return currentParser.onStatus(new FastBuffer(currentBufferRef.buffer, start, len)) || 0
       },
       wasm_on_message_begin: (p) => {
-        assert.strictEqual(currentParser.ptr, p)
+        assert(currentParser.ptr === p)
         return currentParser.onMessageBegin() || 0
       },
       wasm_on_header_field: (p, at, len) => {
-        assert.strictEqual(currentParser.ptr, p)
+        assert(currentParser.ptr === p)
         const start = at - currentBufferPtr + currentBufferRef.byteOffset
         return currentParser.onHeaderField(new FastBuffer(currentBufferRef.buffer, start, len)) || 0
       },
       wasm_on_header_value: (p, at, len) => {
-        assert.strictEqual(currentParser.ptr, p)
+        assert(currentParser.ptr === p)
         const start = at - currentBufferPtr + currentBufferRef.byteOffset
         return currentParser.onHeaderValue(new FastBuffer(currentBufferRef.buffer, start, len)) || 0
       },
       wasm_on_headers_complete: (p, statusCode, upgrade, shouldKeepAlive) => {
-        assert.strictEqual(currentParser.ptr, p)
+        assert(currentParser.ptr === p)
         return currentParser.onHeadersComplete(statusCode, Boolean(upgrade), Boolean(shouldKeepAlive)) || 0
       },
       wasm_on_body: (p, at, len) => {
-        assert.strictEqual(currentParser.ptr, p)
+        assert(currentParser.ptr === p)
         const start = at - currentBufferPtr + currentBufferRef.byteOffset
         return currentParser.onBody(new FastBuffer(currentBufferRef.buffer, start, len)) || 0
       },
       wasm_on_message_complete: (p) => {
-        assert.strictEqual(currentParser.ptr, p)
+        assert(currentParser.ptr === p)
         return currentParser.onMessageComplete() || 0
       }
 
@@ -363,20 +363,19 @@ class Parser {
     const { upgrade, client, socket, headers, statusCode } = this
 
     assert(upgrade)
+    assert(client[kSocket] === socket)
+    assert(!socket.destroyed)
+    assert(!this.paused)
+    assert((headers.length & 1) === 0)
 
     const request = client[kQueue][client[kRunningIdx]]
     assert(request)
-
-    assert(!socket.destroyed)
-    assert(socket === client[kSocket])
-    assert(!this.paused)
     assert(request.upgrade || request.method === 'CONNECT')
 
     this.statusCode = null
     this.statusText = ''
     this.shouldKeepAlive = null
 
-    assert(this.headers.length % 2 === 0)
     this.headers = []
     this.headersSize = 0
 
@@ -433,7 +432,7 @@ class Parser {
       return -1
     }
 
-    assert.strictEqual(this.timeoutType, TIMEOUT_HEADERS)
+    assert(this.timeoutType === TIMEOUT_HEADERS)
 
     this.statusCode = statusCode
     this.shouldKeepAlive = (
@@ -466,7 +465,7 @@ class Parser {
       return 2
     }
 
-    assert(this.headers.length % 2 === 0)
+    assert((this.headers.length & 1) === 0)
     this.headers = []
     this.headersSize = 0
 
@@ -523,7 +522,7 @@ class Parser {
     const request = client[kQueue][client[kRunningIdx]]
     assert(request)
 
-    assert.strictEqual(this.timeoutType, TIMEOUT_BODY)
+    assert(this.timeoutType === TIMEOUT_BODY)
     if (this.timeout) {
       // istanbul ignore else: only for jest
       if (this.timeout.refresh) {
@@ -556,11 +555,12 @@ class Parser {
       return
     }
 
+    assert(statusCode >= 100)
+    assert((this.headers.length & 1) === 0)
+
     const request = client[kQueue][client[kRunningIdx]]
     assert(request)
 
-    assert(statusCode >= 100)
-
     this.statusCode = null
     this.statusText = ''
     this.bytesRead = 0
@@ -568,7 +568,6 @@ class Parser {
     this.keepAlive = ''
     this.connection = ''
 
-    assert(this.headers.length % 2 === 0)
     this.headers = []
     this.headersSize = 0
 
@@ -587,7 +586,7 @@ class Parser {
     client[kQueue][client[kRunningIdx]++] = null
 
     if (socket[kWriting]) {
-      assert.strictEqual(client[kRunning], 0)
+      assert(client[kRunning] === 0)
       // Response completed before request.
       util.destroy(socket, new InformationalError('reset'))
       return constants.ERROR.PAUSED
@@ -646,10 +645,10 @@ async function connectH1 (client, socket) {
   socket[kParser] = new Parser(client, socket, llhttpInstance)
 
   addListener(socket, 'error', function (err) {
-    const parser = this[kParser]
-
     assert(err.code !== 'ERR_TLS_CERT_ALTNAME_INVALID')
 
+    const parser = this[kParser]
+
     // On Mac OS, we get an ECONNRESET even if there is a full body to be forwarded
     // to the user.
     if (err.code === 'ECONNRESET' && parser.statusCode && !parser.shouldKeepAlive) {
diff --git a/lib/dispatcher/client.js b/lib/dispatcher/client.js
index cb61206b1ed..7e22aa000ba 100644
--- a/lib/dispatcher/client.js
+++ b/lib/dispatcher/client.js
@@ -385,6 +385,10 @@ function onError (client, err) {
   }
 }
 
+/**
+ * @param {Client} client
+ * @returns
+ */
 async function connect (client) {
   assert(!client[kConnecting])
   assert(!client[kHTTPContext])