diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router.ts b/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
index 2f3d03c..c2f5678 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
@@ -761,7 +761,10 @@
 
   /**  Page.js middleware that try parse the querystring into queryMap. */
   _queryStringMiddleware(ctx: PageContext, next: PageNextCallback) {
-    let queryMap: Map<string, string> | URLSearchParams = new Map();
+    let queryMap: Map<string, string> | URLSearchParams = new Map<
+      string,
+      string
+    >();
     if (ctx.querystring) {
       // https://caniuse.com/#search=URLSearchParams
       if (window.URLSearchParams) {
diff --git a/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts b/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
index 197a0c4..f85667c 100644
--- a/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
+++ b/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
@@ -299,7 +299,7 @@
       lastNotify: {left: 1, right: 1},
     };
 
-    const rangesCache = new Map();
+    const rangesCache = new Map<string, SyntaxLayerRange[]>();
 
     this._processPromise = util.makeCancelable(
       this._loadHLJS().then(
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts
index 43a6af4..616ec02 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts
@@ -74,7 +74,10 @@
   // Returns the cache for the current canonical path.
   _cache(): Map<string, unknown> {
     if (!this._data.has(window.CANONICAL_PATH)) {
-      this._data.set(window.CANONICAL_PATH, new Map());
+      this._data.set(
+        window.CANONICAL_PATH,
+        new Map<string, ParsedJSON | null>()
+      );
     }
     return this._data.get(window.CANONICAL_PATH) as Map<
       string,
@@ -111,7 +114,7 @@
   }
 
   invalidatePrefix(prefix: string) {
-    const newMap = new Map();
+    const newMap = new Map<string, unknown>();
     for (const [key, value] of this._cache().entries()) {
       if (!key.startsWith(prefix)) {
         newMap.set(key, value);
diff --git a/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts b/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts
index a474909..881e102 100644
--- a/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts
+++ b/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts
@@ -796,10 +796,10 @@
       _shortcut_v_key_last_pressed: number | null = null;
 
       @property({type: Object})
-      _shortcut_go_table: Map<string, string> = new Map();
+      _shortcut_go_table: Map<string, string> = new Map<string, string>();
 
       @property({type: Object})
-      _shortcut_v_table: Map<string, string> = new Map();
+      _shortcut_v_table: Map<string, string> = new Map<string, string>();
 
       Shortcut = Shortcut;
 
diff --git a/polygerrit-ui/app/services/app-context-init.ts b/polygerrit-ui/app/services/app-context-init.ts
index 13a9c76..5c5a37c 100644
--- a/polygerrit-ui/app/services/app-context-init.ts
+++ b/polygerrit-ui/app/services/app-context-init.ts
@@ -27,7 +27,7 @@
 type ServiceCreator<T> = () => T;
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-const initializedServices: Map<ServiceName, any> = new Map();
+const initializedServices: Map<ServiceName, any> = new Map<ServiceName, any>();
 
 function getService<K extends ServiceName>(
   serviceName: K,
diff --git a/polygerrit-ui/app/services/gr-event-interface/gr-event-interface_impl.ts b/polygerrit-ui/app/services/gr-event-interface/gr-event-interface_impl.ts
index f1e0990..d8c5d77 100644
--- a/polygerrit-ui/app/services/gr-event-interface/gr-event-interface_impl.ts
+++ b/polygerrit-ui/app/services/gr-event-interface/gr-event-interface_impl.ts
@@ -127,7 +127,7 @@
     if (eventName) {
       this._listenersMap.set(eventName, []);
     } else {
-      this._listenersMap = new Map();
+      this._listenersMap = new Map<string, EventCallback[]>();
     }
   }
 }
diff --git a/polygerrit-ui/app/utils/patch-set-util.ts b/polygerrit-ui/app/utils/patch-set-util.ts
index cb0bdec..320cc80 100644
--- a/polygerrit-ui/app/utils/patch-set-util.ts
+++ b/polygerrit-ui/app/utils/patch-set-util.ts
@@ -225,7 +225,7 @@
     return patchNums;
   }
   // TODO(TS): replace with Map<PatchNum, boolean>
-  const psWip: Map<string, boolean> = new Map();
+  const psWip: Map<string, boolean> = new Map<string, boolean>();
   let wip = !!change.work_in_progress;
   for (let i = 0; i < change.messages.length; i++) {
     const msg = change.messages[i];