feat: Extend res.links() to allow adding multiple links with the same rel (closes #2729)

Author: andvea

History.md

@@ -10,6 +10,7 @@ unreleased
 * refactor: prefix built-in node module imports
 * Remove unused `depd` dependency
 * Add support for `Uint8Array` in `res.send`
+* Extend res.links() to allow adding multiple links with the same rel
 * deps: debug@^4.4.0
 * deps: body-parser@^2.1.0
 * deps: router@^2.1.0

lib/response.js

@@ -92,7 +92,14 @@ res.links = function(links){
   var link = this.get('Link') || '';
   if (link) link += ', ';
   return this.set('Link', link + Object.keys(links).map(function(rel){
-    return '<' + links[rel] + '>; rel="' + rel + '"';
+    // Allow multiple links if links[rel] is an array
+    if (Array.isArray(links[rel])) {
+      return links[rel].map(function(singleLink){
+        return '<' + singleLink + '>; rel="' + rel + '"';
+      }).join(', ');
+    }else{
+      return '<' + links[rel] + '>; rel="' + rel + '"';
+    }
   }).join(', '));
 };
 

test/res.links.js

@@ -43,5 +43,23 @@ describe('res', function(){
       .expect('Link', '<http://api.example.com/users?page=2>; rel="next", <http://api.example.com/users?page=5>; rel="last", <http://api.example.com/users?page=1>; rel="prev"')
       .expect(200, done);
     })
+
+    it('should set multiple links for single rel', function (done) {
+      var app = express();
+
+      app.use(function (req, res) {
+        res.links({
+          next: 'http://api.example.com/users?page=2',
+          last: ['http://api.example.com/users?page=5', 'http://api.example.com/users?page=1']
+        });
+
+        res.end();
+      });
+
+      request(app)
+      .get('/')
+      .expect('Link', '<http://api.example.com/users?page=2>; rel="next", <http://api.example.com/users?page=5>; rel="last", <http://api.example.com/users?page=1>; rel="last"')
+      .expect(200, done);
+    })
   })
 })