req.accepts: default to first 'type'

docs/api/request.md

@@ -177,12 +177,16 @@ this.is('html');
 ### req.accepts(types)
 
   Check if the given `type(s)` is acceptable, returning
-  the best match when true, otherwise `undefined`, in which
+  the best match when true, otherwise `false`, in which
   case you should respond with 406 "Not Acceptable".
 
   The `type` value may be one or more mime type string
   such as "application/json", the extension name
-  such as "json", or an array `["json", "html", "text/plain"]`. When a list or array is given the _best_ match, if any is returned.
+  such as "json", or an array `["json", "html", "text/plain"]`.
+  When a list or array is given the _best_ match, if any is returned.
+
+  Note that if the client did not send an `Accept` header,
+  the first `type` will be returned.
 
 ```js
 // Accept: text/html
@@ -218,6 +222,7 @@ switch (this.accepts('json', 'html', 'text')) {
   case 'json': break;
   case 'html': break;
   case 'text': break;
+  case false: break;
 }
 ```
 

lib/request.js

@@ -404,6 +404,7 @@ module.exports = {
     if (!Array.isArray(types)) types = [].slice.call(arguments);
     var n = new Negotiator(this.req);
     if (!types.length) return n.preferredMediaTypes();
+    if (!this.header.accept) return types[0];
     var mimes = types.map(extToMime);
     var accepts = n.preferredMediaTypes(mimes);
     var first = accepts[0];

test/request/accepts.js

@@ -3,6 +3,7 @@ var context = require('../context');
 
 describe('ctx.accepts(types)', function(){
   describe('with no arguments', function(){
+    describe('when Accept is populated', function(){
       it('should return all accepted types', function(){
         var ctx = context();
         ctx.req.headers.accept = 'application/*;q=0.2, image/jpeg;q=0.8, text/html, text/plain';
@@ -10,10 +11,28 @@ describe('ctx.accepts(types)', function(){
       })
     })
 
+    describe('when Accept is not populated', function(){
+      it('should return []', function(){
+        var ctx = context();
+        ctx.accepts().should.eql([]);
+      })
+    })
+  })
+
   describe('with no valid types', function(){
+    describe('when Accept is populated', function(){
       it('should return false', function(){
         var ctx = context();
-      ctx.accepts('', 'hey').should.be.false;
+        ctx.req.headers.accept = 'application/*;q=0.2, image/jpeg;q=0.8, text/html, text/plain';
+        ctx.accepts('image/png', 'image/tiff').should.be.false;
+      })
+    })
+
+    describe('when Accept is not populated', function(){
+      it('should return the first type', function(){
+        var ctx = context();
+        ctx.accepts('text/html', 'text/plain', 'image/jpeg', 'application/*').should.equal('text/html');
+      })
     })
   })