From 2ce14e5b6d87a5c8ecbc658921176fb50c987f75 Mon Sep 17 00:00:00 2001
From: Nate Moore <git@natemoo.re>
Date: Fri, 21 Aug 2026 21:22:40 -0400
Subject: [PATCH] feat: update() no-op on same dimensions, throw on invalid

---
 term.ts           | 19 ++++++++++++++++---
 test/term.test.ts | 12 ++++++++++++
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/term.ts b/term.ts
index ec78594..de84d4b 100644
--- a/term.ts
+++ b/term.ts
@@ -230,12 +230,25 @@ export async function createTerm(options: TermOptions): Promise<Term> {
       return { output, events, info, errors, animating };
     },
     update(options: UpdateOptions): void {
+      let w: number;
+      let h: number;
       if ("events" in options) {
         return;
+      } else {
+        w = options.width;
+        h = options.height;
+      }
+      if (
+        !Number.isInteger(w) || !Number.isInteger(h) || w <= 0 || h <= 0
+      ) {
+        throw new RangeError(`invalid terminal dimensions ${w}x${h}`);
+      }
+      if (w === width && h === height) {
+        return;
       }
-      width = options.width;
-      height = options.height;
-      native.update(width, height);
+      width = w;
+      height = h;
+      native.update(w, h);
     },
   };
 }
diff --git a/test/term.test.ts b/test/term.test.ts
index c3f2671..601e2da 100644
--- a/test/term.test.ts
+++ b/test/term.test.ts
@@ -358,6 +358,18 @@ describe("term", () => {
       expect(out.length).toBeGreaterThan(0);
     });
 
+    it("is a no-op when dimensions are unchanged", () => {
+      term.render(frame);
+      term.update({ width: 40, height: 10 });
+      expect(term.render(frame).output.length).toBe(0);
+    });
+
+    it("throws on non-positive or non-integer dimensions", () => {
+      expect(() => term.update({ width: 0, height: 10 })).toThrow(RangeError);
+      expect(() => term.update({ width: 40, height: -1 })).toThrow(RangeError);
+      expect(() => term.update({ width: 40.5, height: 10 })).toThrow(RangeError);
+    });
+
     it("resizes in place and lays out at the new dimensions", () => {
       term.render(frame);
       term.update({ width: 12, height: 4 });
-- 
2.51.2