Fixes #5985 (#5986)

* Fixes #5985

* Update confirm-fixture.js

---------

Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

5 files changed, 50 insertions, 7 deletions

diff --git a/src/bun.js/bindings/FFI.zig b/src/bun.js/bindings/FFI.zig
index 9d16bd78e..da98438ba 100644
--- a/src/bun.js/bindings/FFI.zig
+++ b/src/bun.js/bindings/FFI.zig
@@ -20,8 +20,9 @@ pub const EncodedJSValue = union_EncodedJSValue;
 pub export var ValueUndefined: EncodedJSValue = EncodedJSValue{
     .asInt64 = @as(i64, @bitCast(@as(c_longlong, @as(c_int, 2) | @as(c_int, 8)))),
 };
+pub const TrueI64 = @as(i64, @bitCast(@as(c_longlong, (@as(c_int, 2) | @as(c_int, 4)) | @as(c_int, 1))));
 pub export var ValueTrue: EncodedJSValue = EncodedJSValue{
-    .asInt64 = @as(i64, @bitCast(@as(c_longlong, (@as(c_int, 2) | @as(c_int, 4)) | @as(c_int, 1)))),
+    .asInt64 = TrueI64,
 };
 pub const JSContext = ?*anyopaque;
 pub inline fn JSVALUE_IS_CELL(arg_val: EncodedJSValue) bool {
diff --git a/src/bun.js/bindings/bindings.zig b/src/bun.js/bindings/bindings.zig
index 6c1e11e34..60f8f9376 100644
--- a/src/bun.js/bindings/bindings.zig
+++ b/src/bun.js/bindings/bindings.zig
@@ -3034,7 +3034,7 @@ pub const JSValue = enum(JSValueReprInt) {
     zero = 0,
     undefined = @as(JSValueReprInt, @bitCast(@as(i64, 0xa))),
     null = @as(JSValueReprInt, @bitCast(@as(i64, 0x2))),
-    true = @as(JSValueReprInt, @bitCast(@as(i64, 0x4))),
+    true = FFI.TrueI64,
     false = @as(JSValueReprInt, @bitCast(@as(i64, 0x6))),
     _,
 
diff --git a/src/bun.js/webcore.zig b/src/bun.js/webcore.zig
index 168c4339b..411d3ed2e 100644
--- a/src/bun.js/webcore.zig
+++ b/src/bun.js/webcore.zig
@@ -107,9 +107,11 @@ fn confirm(globalObject: *JSC.JSGlobalObject, callframe: *JSC.CallFrame) callcon
 
     // 6. Pause until the user responds either positively or negatively.
     var stdin = std.io.getStdIn();
-    var reader = stdin.reader();
+    var unbuffered_reader = stdin.reader();
+    var buffered = std.io.bufferedReader(unbuffered_reader);
+    var reader = buffered.reader();
 
-    const first_byte = reader.readByte() catch {
+    var first_byte = reader.readByte() catch {
         return .false;
     };
 
@@ -122,13 +124,14 @@ fn confirm(globalObject: *JSC.JSGlobalObject, callframe: *JSC.CallFrame) callcon
         'y', 'Y' => {
             const next_byte = reader.readByte() catch {
                 // They may have said yes, but the stdin is invalid.
+
                 return .false;
             };
 
             if (next_byte == '\n') {
                 // 8. If the user responded positively, return true;
                 //    otherwise, the user responded negatively: return false.
-                return .false;
+                return .true;
             }
         },
         else => {},
diff --git a/test/js/web/confirm-fixture.js b/test/js/web/confirm-fixture.js
new file mode 100644
index 000000000..908570bce
--- /dev/null
+++ b/test/js/web/confirm-fixture.js
@@ -0,0 +1,3 @@
+const result = confirm("What is your answer?");
+
+console.error(result ? "Yes" : "No");
diff --git a/test/js/web/web-globals.test.js b/test/js/web/web-globals.test.js
index abcad63f7..74b28c0b0 100644
--- a/test/js/web/web-globals.test.js
+++ b/test/js/web/web-globals.test.js
@@ -1,6 +1,6 @@
-import { unsafe } from "bun";
+import { spawn } from "bun";
 import { expect, it, test } from "bun:test";
-import { withoutAggressiveGC } from "harness";
+import { bunEnv, bunExe, withoutAggressiveGC } from "harness";
 
 test("exists", () => {
   expect(typeof URL !== "undefined").toBe(true);
@@ -233,3 +233,39 @@ test("navigator", () => {
     expect(navigator.platform).toBe("Linux x86_64");
   }
 });
+
+test("confirm (yes)", async () => {
+  const proc = spawn({
+    cmd: [bunExe(), require("path").join(import.meta.dir, "./confirm-fixture.js")],
+    stderr: "pipe",
+    stdin: "pipe",
+    stdout: "pipe",
+    env: bunEnv,
+  });
+
+  proc.stdin.write("Y");
+  await proc.stdin.flush();
+
+  proc.stdin.write("\n");
+  await proc.stdin.flush();
+
+  await proc.exited;
+
+  expect(await new Response(proc.stderr).text()).toBe("Yes\n");
+});
+
+test("confirm (no)", async () => {
+  const proc = spawn({
+    cmd: [bunExe(), require("path").join(import.meta.dir, "./confirm-fixture.js")],
+    stderr: "pipe",
+    stdin: "pipe",
+    stdout: "pipe",
+    env: bunEnv,
+  });
+
+  proc.stdin.write("poask\n");
+  await proc.stdin.flush();
+  await proc.exited;
+
+  expect(await new Response(proc.stderr).text()).toBe("No\n");
+});