update tests and comments

Author: SRHerzog

lib/internal/validators.js

@@ -459,6 +459,14 @@ function validateUnion(value, name, union) {
   }
 }
 
+/*
+  The rules for the Link header field are described here:
+  https://www.rfc-editor.org/rfc/rfc8288.html#section-3
+
+  This regex validates any string surrounded by angle brackets
+  (not necessarily a valid URI reference) followed by zero or more
+  link-params separated by semicolons.
+*/
 const linkValueRegExp = /^(?:<[^>]*>)(?:\s*;\s*[^;"\s]+(?:=(")?[^;"\s]*\1)?)*$/;
 
 /**

test/parallel/test-http-early-hints-invalid-argument.js

@@ -13,6 +13,24 @@ const testResBody = 'response content\n';
       res.writeEarlyHints('bad argument type');
     }, (err) => err.code === 'ERR_INVALID_ARG_TYPE');
 
+    assert.throws(() => {
+      res.writeEarlyHints({
+        link: '</>; '
+      });
+    }, (err) => err.code === 'ERR_INVALID_ARG_VALUE');
+
+    assert.throws(() => {
+      res.writeEarlyHints({
+        link: 'rel=preload; </scripts.js>'
+      });
+    }, (err) => err.code === 'ERR_INVALID_ARG_VALUE');
+
+    assert.throws(() => {
+      res.writeEarlyHints({
+        link: 'invalid string'
+      });
+    }, (err) => err.code === 'ERR_INVALID_ARG_VALUE');
+
     debug('Server sending full response...');
     res.end(testResBody);
     server.close();
@@ -33,11 +51,6 @@ const testResBody = 'response content\n';
 {
   const server = http.createServer(common.mustCall((req, res) => {
     debug('Server sending early hints...');
-    assert.throws(() => {
-      res.writeEarlyHints({
-        link: '</>; '
-      });
-    }, (err) => err.code === 'ERR_INVALID_ARG_VALUE');
 
     debug('Server sending full response...');
     res.end(testResBody);

test/parallel/test-http-early-hints.js

@@ -58,6 +58,7 @@ const testResBody = 'response content\n';
     res.writeEarlyHints({
       link: [
         '</styles.css>; rel=preload; as=style',
+        '</scripts.js>; crossorigin; rel=preload; as=script',
         '</scripts.js>; rel=preload; as=script; crossorigin',
       ]
     });
@@ -75,7 +76,7 @@ const testResBody = 'response content\n';
     req.on('information', common.mustCall((res) => {
       assert.strictEqual(
         res.headers.link,
-        '</styles.css>; rel=preload; as=style, </scripts.js>; rel=preload; as=script; crossorigin'
+        '</styles.css>; rel=preload; as=style, </scripts.js>; crossorigin; rel=preload; as=script, </scripts.js>; rel=preload; as=script; crossorigin'
       );
     }));