Support array of fields to set

closes #2

History.md

@@ -1,3 +1,8 @@
+unreleased
+==========
+
+  * Support array of fields to set
+
 0.0.0 / 2014-06-04
 ==================
 

README.md

@@ -18,16 +18,18 @@ $ npm install vary
 var vary = require('vary')
 ```
 
-### vary(res, header)
+### vary(res, field)
 
-Adds the given `header` to the `Vary` response header of `res`.
+Adds the given header `field` to the `Vary` response header of `res`.
+This can be a string of a single field or an array of multiple fields.
 
 This will append the header if not already listed, otherwise leaves
 it listed in the current location.
 
 ```js
 vary(res, 'Origin')
 vary(res, 'User-Agent')
+vary(res, ['Accept', 'Accept-Language', 'Accept-Encoding'])
 ```
 
 ## Testing

index.js

@@ -17,25 +17,31 @@ module.exports = vary;
 var separators = /[\(\)<>@,;:\\"\/\[\]\?=\{\}\u0020\u0009]/;
 
 /**
- * Mark that a request is varied on a header.
+ * Mark that a request is varied on a header field.
  *
  * @param {Object} res
- * @param {String} header
+ * @param {String|Array} field
  * @api public
  */
 
-function vary(res, header) {
+function vary(res, field) {
   if (!res || !res.getHeader || !res.setHeader) {
     // quack quack
     throw new TypeError('res argument is required');
   }
 
-  if (!header) {
-    throw new TypeError('header argument is required');
+  if (!field) {
+    throw new TypeError('field argument is required');
   }
 
-  if (separators.test(header)) {
-    throw new TypeError('header argument is not a valid header');
+  var fields = !Array.isArray(field)
+    ? [String(field)]
+    : field;
+
+  for (var i = 0; i < fields.length; i++) {
+    if (separators.test(fields[i])) {
+      throw new TypeError('field argument contains an invalid header');
+    }
   }
 
   var val = res.getHeader('Vary') || ''
@@ -52,20 +58,22 @@ function vary(res, header) {
   var vals = headers.toLowerCase().split(/ *, */);
 
   // unspecified vary
-  if (header === '*' || vals.indexOf('*') !== -1) {
+  if (fields.indexOf('*') !== -1 || vals.indexOf('*') !== -1) {
     res.setHeader('Vary', '*');
     return;
   }
 
-  if (vals.indexOf(header.toLowerCase()) !== -1) {
-    // already set
-    return;
-  }
+  for (var i = 0; i < fields.length; i++) {
+    field = fields[i].toLowerCase();
 
-  // append value (case-preserving)
-  val = headers
-    ? headers + ', ' + header
-    : header;
+    // append value (case-preserving)
+    if (vals.indexOf(field) === -1) {
+      vals.push(field);
+      headers = headers
+        ? headers + ', ' + fields[i]
+        : fields[i];
+    }
+  }
 
-  res.setHeader('Vary', val);
+  res.setHeader('Vary', headers);
 }

test/test.js

@@ -14,16 +14,27 @@ describe('vary(res, header)', function () {
       });
     });
 
-    describe('header', function () {
+    describe('field', function () {
       it('should be required', function () {
         var res = createRes();
-        vary.bind(null, res).should.throw(/header.*required/);
+        vary.bind(null, res).should.throw(/field.*required/);
+      });
+
+      it('should accept string', function () {
+        var res = createRes();
+        vary.bind(null, res, 'foo').should.not.throw();
+      });
+
+      it('should accept array of string', function () {
+        var res = createRes();
+        vary.bind(null, res, ['foo', 'bar']).should.not.throw();
       });
 
       it('should not allow separators', function () {
         var res = createRes();
-        vary.bind(null, res, 'invalid:header').should.throw(/header.*not.*valid/);
-        vary.bind(null, res, 'invalid header').should.throw(/header.*not.*valid/);
+        vary.bind(null, res, 'invalid:header').should.throw(/field.*contains.*invalid/);
+        vary.bind(null, res, 'invalid header').should.throw(/field.*contains.*invalid/);
+        vary.bind(null, res, ['invalid header']).should.throw(/field.*contains.*invalid/);
       });
     });
   });
@@ -125,6 +136,38 @@ describe('vary(res, header)', function () {
       res.getHeader('Vary').should.equal('*');
     });
   });
+
+  describe('when fields is array', function () {
+    it('should set value', function () {
+      var res = createRes();
+      vary(res, ['Accept', 'Accept-Language']);
+      res.getHeader('Vary').should.equal('Accept, Accept-Language');
+    });
+
+    it('should ignore double-entries', function () {
+      var res = createRes();
+      vary(res, ['Accept', 'Accept']);
+      res.getHeader('Vary').should.equal('Accept');
+    });
+
+    it('should be case-insensitive', function () {
+      var res = createRes();
+      vary(res, ['Accept', 'ACCEPT']);
+      res.getHeader('Vary').should.equal('Accept');
+    });
+
+    it('should handle contained *', function () {
+      var res = createRes();
+      vary(res, ['Origin', 'User-Agent', '*', 'Accept']);
+      res.getHeader('Vary').should.equal('*');
+    });
+
+    it('should handle existing values', function () {
+      var res = createRes({'vary': 'Accept, Accept-Encoding'});
+      vary(res, ['origin', 'accept', 'accept-charset']);
+      res.getHeader('Vary').should.equal('Accept, Accept-Encoding, origin, accept-charset');
+    });
+  });
 });
 
 function createRes(headers) {