Treat tabs as XML characters, per spec

lib/serialization.js

@@ -6,7 +6,7 @@ const xnv = require("xml-name-validator");
 const attributeUtils = require("./attributes");
 const { NAMESPACES, VOID_ELEMENTS, NODE_TYPES } = require("./constants");
 
-const XML_CHAR = /^(\x20|\x0D|\x0A|[ -\uD7FF]|[\uE000-\uFFFD]|(?:[\uD800-\uDBFF][\uDC00-\uDFFF]))*$/;
+const XML_CHAR = /^(\x09|\x0A|\x0D|[\x20-\uD7FF]|[\uE000-\uFFFD]|(?:[\uD800-\uDBFF][\uDC00-\uDFFF]))*$/;
 const PUBID_CHAR = /^(\x20|\x0D|\x0A|[a-zA-Z0-9]|[-'()+,./:=?;!*#@$_%])*$/;
 
 function asciiCaseInsensitiveMatch(a, b) {

test/jsdom.test.js

@@ -1,14 +1,19 @@
 const { JSDOM } = require("jsdom");
 
 const XMLSerializer = require("../lib/XMLSerializer").interface;
+const { produceXMLSerialization } = require("../lib/serialization");
 
 function serialize(node) {
   var serializer = new XMLSerializer();
   return serializer.serializeToString(node);
 }
 
+function wellFormedSerialize(node) {
+  return produceXMLSerialization(node, true);
+}
+
 describe("JSDOM imports", () => {
-  test("Serializes custom prefixes", function() {
+  test("Serializes custom prefixes", () => {
     const {
       window: { document }
     } = new JSDOM(
@@ -26,4 +31,18 @@ describe("JSDOM imports", () => {
       `<element xmlns:prefix="https://example.com/" prefix:hasOwnProperty="value"/>`
     );
   });
+
+  test("Serializes tab characters", () => {
+    const {
+      window: { document }
+    } = new JSDOM(
+      `<dummy />`,
+      { contentType: "text/xml" }
+    );
+
+    const el = document.createElement("el");
+    el.appendChild(document.createTextNode("\t"));
+
+    expect(wellFormedSerialize(el)).toEqual("<el>\t</el>");
+  });
 });