feat(unenv-preset): add native node:tty module support (#12023)

petebacondarwin · web-flow · commit 7f181839513a · 2026-02-13T14:25:07.000Z
diff --git a/.changeset/native-node-tty.md b/.changeset/native-node-tty.md
@@ -0,0 +1,7 @@
+---
+"@cloudflare/unenv-preset": minor
+---
+
+Add support for native `node:tty` module from workerd when the `enable_nodejs_tty_module` compatibility flag is enabled.
+
+This feature is currently experimental and requires `nodejs_compat`, `experimental`, and `enable_nodejs_tty_module` compatibility flags to be set.
diff --git a/packages/unenv-preset/package.json b/packages/unenv-preset/package.json
@@ -49,7 +49,7 @@
 	},
 	"peerDependencies": {
 		"unenv": "2.0.0-rc.24",
-		"workerd": "^1.20260115.0"
+		"workerd": "^1.20260213.0"
 	},
 	"peerDependenciesMeta": {
 		"workerd": {
diff --git a/packages/unenv-preset/src/preset.ts b/packages/unenv-preset/src/preset.ts
@@ -81,6 +81,7 @@ export function getCloudflarePreset({
 	const replOverrides = getReplOverrides(compat);
 	const processOverrides = getProcessOverrides(compat);
 	const v8Overrides = getV8Overrides(compat);
+	const ttyOverrides = getTtyOverrides(compat);
 
 	// "dynamic" as they depend on the compatibility date and flags
 	const dynamicNativeModules = [
@@ -103,6 +104,7 @@ export function getCloudflarePreset({
 		...replOverrides.nativeModules,
 		...processOverrides.nativeModules,
 		...v8Overrides.nativeModules,
+		...ttyOverrides.nativeModules,
 	];
 
 	// "dynamic" as they depend on the compatibility date and flags
@@ -125,6 +127,7 @@ export function getCloudflarePreset({
 		...replOverrides.hybridModules,
 		...processOverrides.hybridModules,
 		...v8Overrides.hybridModules,
+		...ttyOverrides.hybridModules,
 	];
 
 	return {
@@ -939,3 +942,39 @@ function getV8Overrides({
 				hybridModules: [],
 			};
 }
+
+/**
+ * Returns the overrides for `node:tty` (unenv or workerd)
+ *
+ * The native tty implementation:
+ * - is experimental and has no default enable date
+ * - can be enabled with the "enable_nodejs_tty_module" flag
+ * - can be disabled with the "disable_nodejs_tty_module" flag
+ */
+function getTtyOverrides({
+	compatibilityFlags,
+}: {
+	compatibilityDate: string;
+	compatibilityFlags: string[];
+}): { nativeModules: string[]; hybridModules: string[] } {
+	const disabledByFlag = compatibilityFlags.includes(
+		"disable_nodejs_tty_module"
+	);
+
+	const enabledByFlag =
+		compatibilityFlags.includes("enable_nodejs_tty_module") &&
+		compatibilityFlags.includes("experimental");
+
+	const enabled = enabledByFlag && !disabledByFlag;
+
+	// When enabled, use the native `tty` module from workerd
+	return enabled
+		? {
+				nativeModules: ["tty"],
+				hybridModules: [],
+			}
+		: {
+				nativeModules: [],
+				hybridModules: [],
+			};
+}
diff --git a/packages/wrangler/e2e/unenv-preset/preset.test.ts b/packages/wrangler/e2e/unenv-preset/preset.test.ts
@@ -655,6 +655,27 @@ const localTestConfigs: TestConfig[] = [
 			},
 		},
 	],
+	// node:tty (experimental, no default enable date)
+	[
+		// TODO: add test for disabled by date (no date defined yet)
+		// TODO: add test for enabled by date (no date defined yet)
+		{
+			name: "tty enabled by flag",
+			compatibilityDate: "2024-09-23",
+			compatibilityFlags: ["enable_nodejs_tty_module", "experimental"],
+			expectRuntimeFlags: {
+				enable_nodejs_tty_module: true,
+			},
+		},
+		{
+			name: "tty disabled by flag",
+			compatibilityDate: "2024-09-23",
+			compatibilityFlags: ["disable_nodejs_tty_module", "experimental"],
+			expectRuntimeFlags: {
+				enable_nodejs_tty_module: false,
+			},
+		},
+	],
 ].flat() as TestConfig[];
 
 describe.each(localTestConfigs)(
diff --git a/packages/wrangler/e2e/unenv-preset/worker/index.ts b/packages/wrangler/e2e/unenv-preset/worker/index.ts
@@ -888,6 +888,31 @@ export const WorkerdTests: Record<string, () => void> = {
 			});
 		}
 	},
+
+	async testTty() {
+		const tty = await import("node:tty");
+
+		// Common exports (both unenv stub and native workerd)
+		assertTypeOfProperties(tty, {
+			isatty: "function",
+			ReadStream: "function",
+			WriteStream: "function",
+		});
+
+		assertTypeOfProperties(tty.default, {
+			isatty: "function",
+			ReadStream: "function",
+			WriteStream: "function",
+		});
+
+		// isatty should return false (both unenv and workerd)
+		assert.strictEqual(tty.isatty(0), false);
+		assert.strictEqual(tty.isatty(1), false);
+		assert.strictEqual(tty.isatty(2), false);
+
+		assert.doesNotThrow(() => new tty.ReadStream(0));
+		assert.doesNotThrow(() => new tty.WriteStream(1));
+	},
 };
 
 /**
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
