Add res.append(field, val) to append headers

docs/api/context.md

@@ -190,6 +190,7 @@ koa uses [http-assert](https://github.com/jshttp/http-assert) for assertions.
  - `ctx.redirect()`
  - `ctx.attachment()`
  - `ctx.set()`
+ - `ctx.append()`
  - `ctx.remove()`
  - `ctx.lastModified=`
  - `ctx.etag=`

docs/api/response.md

@@ -151,6 +151,13 @@ var etag = this.get('ETag');
 this.set('Cache-Control', 'no-cache');
 ```
 
+### response.append(field, value)
+ Append additional header `field` with value `val`.
+
+```js
+this.append('Link', '<https://127.0.0.1/>');
+```
+
 ### response.set(fields)
 
  Set several response header `fields` with an object:

lib/context.js

@@ -147,6 +147,7 @@ delegate(proto, 'response')
  .method('remove')
  .method('vary')
  .method('set')
+ .method('append')
  .access('status')
  .access('message')
  .access('body')

lib/response.js

@@ -424,6 +424,33 @@ module.exports = {
  }
  },
 
+ /**
+ * Append additional header `field` with value `val`.
+ *
+ * Examples:
+ *
+ * this.append('Link', ['<https://localhost/>', '<https://localhost:3000/>']);
+ * this.append('Set-Cookie', 'foo=bar; Path=/; HttpOnly');
+ * this.append('Warning', '199 Miscellaneous warning');
+ *
+ * @param {String} field
+ * @param {String|Array} val
+ * @api public
+ */
+
+ append: function(field, val){
+ var prev = this.get(field);
+ var value = val;
+ if (prev) {
+ // concat the new and prev vals
+ value = Array.isArray(prev) ? prev.concat(val)
+ : Array.isArray(val) ? [prev].concat(val)
+ : [prev, val];
+ }
+
+ return this.set(field, value);
+ },
+
  /**
  * Remove header `field`.
  *

test/response/append.js

@@ -0,0 +1,38 @@
+
+var context = require('../context');
+
+describe('ctx.append(name, val)', function(){
+ it('should append multiple headers', function(){
+ var ctx = context();
+ ctx.append('x-foo', 'bar1');
+ ctx.append('x-foo', 'bar2');
+ ctx.response.header['x-foo'].should.eql(['bar1', 'bar2']);
+ })
+
+ it('should accept array of values', function (){
+ var ctx = context();
+
+ ctx.append('Set-Cookie', ['foo=bar', 'fizz=buzz']);
+ ctx.response.header['set-cookie'].should.eql(['foo=bar', 'fizz=buzz']);
+ })
+
+ it('should get reset by res.set(field, val)', function (){
+ var ctx = context();
+
+ ctx.append('Link', '<https://localhost/>');
+ ctx.append('Link', '<https://localhost:80/>');
+
+ ctx.set('Link', '<https://127.0.0.1/>');
+
+ ctx.response.header.link.should.equal('<https://127.0.0.1/>');
+ })
+
+ it('should work with res.set(field, val) first', function (){
+ var ctx = context();
+
+ ctx.set('Link', '<https://localhost/>');
+ ctx.append('Link', '<https://localhost:80/>');
+
+ ctx.response.header.link.should.eql(['<https://localhost/>', '<https://localhost:80/>']);
+ })
+})