Fixes #3674

11ty · Mar 4, 2025 · 6957ff4 · 6957ff4
1 parent fa30c8a
commit 6957ff4
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Showing 2 changed files with 25 additions and 1 deletion.
diff --git a/src/Template.js b/src/Template.js
@@ -1035,7 +1035,7 @@ class Template extends TemplateContent {
 
 		if (dateValue) {
 			debug("getMappedDate: using a date in the data for %o of %o", this.inputPath, data.date);
-			if (dateValue instanceof DateTime) {
+			if (dateValue?.constructor?.name === "DateTime") {
 				// YAML does its own date parsing
 				debug("getMappedDate: found DateTime instance: %o", dateValue);
 				return dateValue.toJSDate();

diff --git a/test/EleventyTest-CustomDateParsing.js b/test/EleventyTest-CustomDateParsing.js
@@ -1,7 +1,10 @@
+import { createRequire } from "node:module";
 import test from "ava";
 import { DateTime } from "luxon";
 import Eleventy from "../src/Eleventy.js";
 
+const require = createRequire(import.meta.url);
+
 test("Custom date parsing callback (return string), Issue #867", async (t) => {
   t.plan(3);
 
@@ -169,3 +172,24 @@ test("Custom date parsing callbacks (two, last wins, return string), Issue #867"
   let [result] = await elev.toJSON();
   t.deepEqual(result.data.page.date, new Date(Date.UTC(2001,0,1,12)));
 });
+
+// https://github.com/11ty/eleventy/issues/3674
+test("instanceof DateTime issue, Issue #3674", async (t) => {
+  const { DateTime } = require("luxon");
+
+  // this test *requires* a non-virtual template to repro
+  let elev = new Eleventy("./test/stubs/index.html", undefined, {
+    config: eleventyConfig => {
+      eleventyConfig.addTemplate("test.html", `# Markdown`);
+      eleventyConfig.dataFilterSelectors.add("page.date");
+
+      eleventyConfig.addDateParsing(function (dateValue) {
+        return DateTime.fromISO("2001-01-01T12:00:00Z");
+      });
+    }
+  });
+  elev.disableLogger();
+
+  let [result] = await elev.toJSON();
+  t.deepEqual(result.data.page.date, new Date(Date.UTC(2001,0,1,12)));
+});