From dc57ba9207266ec96af1a66de2560bc953d5eb5e Mon Sep 17 00:00:00 2001
From: Renegade334 <contact.9a5d6388@renegade334.me.uk>
Date: Wed, 6 May 2026 03:21:00 +0100
Subject: [PATCH] inspect: add Temporal support

Signed-off-by: Renegade334 <contact.9a5d6388@renegade334.me.uk>
---
 lib/internal/util/inspect.js | 50 ++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/lib/internal/util/inspect.js b/lib/internal/util/inspect.js
index c611eb97fc0755..03d5ed0cb6e4a9 100644
--- a/lib/internal/util/inspect.js
+++ b/lib/internal/util/inspect.js
@@ -218,6 +218,47 @@ const builtInObjects = new SafeSet(
 // https://tc39.es/ecma262/#sec-IsHTMLDDA-internal-slot
 const isUndetectableObject = (v) => typeof v === 'undefined' && v !== undefined;
 
+const temporalConstructors = [
+  { name: 'Duration', fullName: 'Temporal.Duration' },
+  { name: 'Instant', fullName: 'Temporal.Instant' },
+  { name: 'PlainDate', fullName: 'Temporal.PlainDate' },
+  { name: 'PlainDateTime', fullName: 'Temporal.PlainDateTime' },
+  { name: 'PlainMonthDay', fullName: 'Temporal.PlainMonthDay' },
+  { name: 'PlainTime', fullName: 'Temporal.PlainTime' },
+  { name: 'PlainYearMonth', fullName: 'Temporal.PlainYearMonth' },
+  { name: 'ZonedDateTime', fullName: 'Temporal.ZonedDateTime' },
+];
+
+// Best-effort, using instanceof. Polyfills will likely pass these checks.
+// Returns void if either the type checks fail or the attempt at calling
+// .toString() fails, so that format() can fall back to standard object
+// formatting in either case.
+// TODO: Hopefully the V8 API will expose typechecks at some point.
+function getTemporalInfo(value) {
+  try {
+    const { Temporal } = globalThis;
+    if (Temporal === undefined) {
+      return;
+    }
+    for (let i = 0; i < temporalConstructors.length; i++) {
+      const entry = temporalConstructors[i];
+      const constructor = Temporal[entry.name];
+      if (typeof constructor !== 'function') {
+        return;
+      }
+      if (!FunctionPrototypeSymbolHasInstance(constructor, value)) {
+        continue;
+      }
+      const { prototype } = constructor;
+      if (!ObjectPrototypeHasOwnProperty(prototype, 'toString')) {
+        return;
+      }
+      const result = FunctionPrototypeCall(prototype.toString, value);
+      return { ...entry, result };
+    }
+  } catch { /* void */ }
+}
+
 // These options must stay in sync with `getUserOptions`. So if any option will
 // be added or removed, `getUserOptions` must also be updated accordingly.
 const inspectDefaultOptions = ObjectSeal({
@@ -1321,6 +1362,7 @@ function formatRaw(ctx, value, recurseTimes, typedArray) {
   if (noIterator) {
     keys = getKeys(value, ctx.showHidden);
     braces = ['{', '}'];
+    let temporalInfo;
     if (typeof value === 'function') {
       base = getFunctionBase(ctx, value, constructor, tag);
       if (keys.length === 0 && protoProps === undefined)
@@ -1404,6 +1446,14 @@ function formatRaw(ctx, value, recurseTimes, typedArray) {
       if (keys.length === 0 && protoProps === undefined) {
         return base;
       }
+    } else if ((temporalInfo = getTemporalInfo(value))) {
+      const prefix = constructor === temporalInfo.name && tag === temporalInfo.fullName ?
+        (temporalInfo.fullName + ' ') :
+        getPrefix(constructor, tag, temporalInfo.fullName);
+      base = `${prefix}${temporalInfo.result}`;
+      if (keys.length === 0 && protoProps === undefined) {
+        return ctx.stylize(base, 'date');
+      }
     } else {
       if (keys.length === 0 && protoProps === undefined) {
         if (isExternal(value)) {