diff --git a/examples/calculator/src/index.tsx b/examples/calculator/src/index.tsx
index 852911990..a2ed8284b 100644
--- a/examples/calculator/src/index.tsx
+++ b/examples/calculator/src/index.tsx
@@ -403,7 +403,7 @@ class CalculatorApp extends Widget {
     }
 
     private evaluate() {
-        if (this.expression.trim() === "") return;
+        if (this.expression.trim().length === 0) return;
         const oldExpr = this.expression;
         this.result = safeEval(this.expression);
         if (this.result !== null && !this.result.startsWith("Error")) {
diff --git a/examples/chat-app/src/index.tsx b/examples/chat-app/src/index.tsx
index a3a2ddb14..0d405714e 100644
--- a/examples/chat-app/src/index.tsx
+++ b/examples/chat-app/src/index.tsx
@@ -257,7 +257,7 @@ function parseBlocks(text: string): Block[] {
         }
 
         // ── Handle Paragraphs ────────────────────────
-        if (line.trim() === '') {
+        if (line.trim().length === 0) {
             blocks.push({
                 type: 'paragraph',
                 text: '',
diff --git a/packages/ui/src/prompts.ts b/packages/ui/src/prompts.ts
index b92bb28ba..b248a6ac4 100644
--- a/packages/ui/src/prompts.ts
+++ b/packages/ui/src/prompts.ts
@@ -113,7 +113,7 @@ async function promptSelect<T = string>(options: SelectPromptOptions<T>): Promis
                     return;
                 }
                 const n = parseInt(trimmed, 10);
-                if (!isNaN(n) && n >= 1 && n <= choices.length) {
+                if (!Number.isNaN(n) && n >= 1 && n <= choices.length) {
                     rl.close();
                     resolve(choices[n - 1].value);
                     return;