diff --git a/scripts/build.sh b/scripts/build.sh
index d70c50dd..51cb6d81 100755
--- a/scripts/build.sh
+++ b/scripts/build.sh
@@ -39,6 +39,7 @@ fi
 # .bracketexpr.generated.ts is needed for metadata generation
 (
 printf '/* tslint:disable:no-trailing-whitespace */\n'
+printf '/* tslint:disable:no-unnecessary-initializer */\n'
 "$(npm bin)/nearleyc" src/grammars/bracketexpr.ne
 ) > src/grammars/.bracketexpr.generated.ts
 
diff --git a/src/background/nearley_utils.ts b/src/background/nearley_utils.ts
index 05e600f6..f2ab41c8 100644
--- a/src/background/nearley_utils.ts
+++ b/src/background/nearley_utils.ts
@@ -13,7 +13,7 @@ export class Parser {
     }
 
     feedUntilError(input) {
-        let lastResult = undefined
+        let lastResult
         let consumedIndex = 0
         try {
             for (let val of input) {
diff --git a/src/commandline_frame.ts b/src/commandline_frame.ts
index ddf5d13d..ad9a91b3 100644
--- a/src/commandline_frame.ts
+++ b/src/commandline_frame.ts
@@ -49,7 +49,7 @@ import * as tri_editor from "@src/lib/editor"
 const logger = new Logger("cmdline")
 
 /** @hidden **/
-let activeCompletions: Completions.CompletionSource[] = undefined
+let activeCompletions: Completions.CompletionSource[]
 /** @hidden **/
 let completionsDiv = window.document.getElementById("completions")
 /** @hidden **/
diff --git a/src/content/controller_content.ts b/src/content/controller_content.ts
index 3c62fab4..20252244 100644
--- a/src/content/controller_content.ts
+++ b/src/content/controller_content.ts
@@ -140,8 +140,7 @@ function* ParserController() {
                 // unbounded length.
                 keyEvents.push(keyevent)
 
-                let response = undefined
-                response = parsers[contentState.mode](keyEvents)
+                let response = parsers[contentState.mode](keyEvents)
                 logger.debug(
                     currentMode,
                     contentState.mode,
diff --git a/src/content/hinting.ts b/src/content/hinting.ts
index 55ce5ee7..f46282e3 100644
--- a/src/content/hinting.ts
+++ b/src/content/hinting.ts
@@ -93,7 +93,7 @@ class HintState {
     }
 }
 
-let modeState: HintState = undefined
+let modeState: HintState
 
 /** For each hintable element, add a hint */
 export function hintPage(
diff --git a/src/content/scrolling.ts b/src/content/scrolling.ts
index d8f7413a..a2abdd8d 100644
--- a/src/content/scrolling.ts
+++ b/src/content/scrolling.ts
@@ -105,7 +105,7 @@ export async function scroll(
     x: number = 0,
     y: number = 0,
     e: Node,
-    duration: number = undefined,
+    duration?: number,
 ) {
     let smooth = await getSmooth()
     if (smooth == "false") duration = 0
@@ -145,8 +145,8 @@ let lastY = 0
 export async function recursiveScroll(
     x: number,
     y: number,
-    node: Element = undefined,
-    stopAt: Element = undefined,
+    node?: Element,
+    stopAt?: Element,
 ) {
     let startingFromCached = false
     if (!node) {
diff --git a/src/excmds.ts b/src/excmds.ts
index 999b9a94..2fe38dc2 100644
--- a/src/excmds.ts
+++ b/src/excmds.ts
@@ -1130,7 +1130,7 @@ export async function url2args() {
 
 /** @hidden */
 //#content_helper
-let sourceElement = undefined
+let sourceElement
 /** @hidden */
 //#content_helper
 function removeSource() {
@@ -1516,7 +1516,7 @@ export function urlparent(count = 1) {
 //#content
 export function urlmodify(mode: "-t" | "-r" | "-q" | "-Q" | "-g", ...args: string[]) {
     let oldUrl = new URL(window.location.href)
-    let newUrl = undefined
+    let newUrl
 
     switch (mode) {
         case "-t":
diff --git a/src/lib/messaging.ts b/src/lib/messaging.ts
index e8778bae..a7711002 100644
--- a/src/lib/messaging.ts
+++ b/src/lib/messaging.ts
@@ -84,7 +84,7 @@ export async function messageTab(tabId, type: TabMessageType, command, args?) {
     return browserBg.tabs.sendMessage(tabId, message)
 }
 
-let _ownTabId = undefined
+let _ownTabId
 export async function messageOwnTab(type: TabMessageType, command, args?) {
     if (_ownTabId === undefined) {
         _ownTabId = await ownTabId()
diff --git a/src/parsers/gobblemode.ts b/src/parsers/gobblemode.ts
index 7ca1c35d..0ad82237 100644
--- a/src/parsers/gobblemode.ts
+++ b/src/parsers/gobblemode.ts
@@ -8,7 +8,7 @@ class GobbleState {
     public endCommand = ""
 }
 
-let modeState: GobbleState = undefined
+let modeState: GobbleState
 
 /** Init gobble mode. After parsing the defined number of input keys, execute
 `endCmd` with attached parsed input. `Escape` cancels the mode and returns to
diff --git a/tslint.json b/tslint.json
index 9a0136bf..6d76af88 100644
--- a/tslint.json
+++ b/tslint.json
@@ -23,7 +23,6 @@
     "no-identical-functions": false,
     "no-shadowed-variable": false,
     "no-string-throw": false,
-    "no-unnecessary-initializer": false,
     "no-unsafe-finally": false,
     "no-var-keyword": false,
     "no-variable-usage-before-declaration": false,