Add option to read multiple cookies with same name

HISTORY.md

@@ -1,3 +1,9 @@
+unreleased
+==================
+
+  * Add support for reading multiple cookies with same name
+    - This feature can be turned on by `multiValuedCookies` flag
+
 0.4.1 / 2020-04-21
 ==================
 

README.md

@@ -51,6 +51,11 @@ sequences into their byte representations.
 **note** if an error is thrown from this function, the original, non-decoded cookie value will
 be returned as the cookie's value.
 
+##### multiValuedCookies
+
+Specifies a boolean flag which if set to `true` would allow reading multiple cookies with same name (key). All values will be put into an array.
+By default (when `multiValuedCookies` isn't present or set to `false`), only first cookie's value is read which is not in accordance with [RFC 6265](https://tools.ietf.org/html/rfc6265#section-4.2.2) (this behaviour is kept around for backward compatibility reason).
+
 ### cookie.serialize(name, value, options)
 
 Serialize a cookie name-value pair into a `Set-Cookie` header string. The `name` argument is the

index.js

@@ -38,7 +38,7 @@ var fieldContentRegExp = /^[\u0009\u0020-\u007e\u0080-\u00ff]+$/;
  * Parse a cookie header.
  *
  * Parse the given cookie header string into an object
- * The object has the various cookies as keys(names) => values
+ * The object has the various cookies as keys(names) => values or array of values
  *
  * @param {string} str
  * @param {object} [options]
@@ -73,9 +73,15 @@ function parse(str, options) {
       val = val.slice(1, -1);
     }
 
-    // only assign once
+    // only assign once unless multiValuedCookies is true
     if (undefined == obj[key]) {
       obj[key] = tryDecode(val, dec);
+    } else if (opt.multiValuedCookies) {
+      if (typeof obj[key] === 'string') {
+        obj[key] = [obj[key], tryDecode(val, dec)];
+      } else {
+        obj[key].push(tryDecode(val, dec));
+      }
     }
   }
 

test/parse.js

@@ -70,3 +70,30 @@ test('assign only once', function() {
   assert.deepEqual({ foo: '', bar: 'bar' },
     cookie.parse('foo=;bar=bar;foo=boo'));
 });
+
+test('multiValuedCookies flag', function () {
+  assert.deepEqual(
+    { foo: ["%1", "boo"], bar: "bar" },
+    cookie.parse("foo=%1;bar=bar;foo=boo", {
+      multiValuedCookies: true
+    })
+  );
+  assert.deepEqual(
+    { foo: ["", "boo"], bar: "bar" },
+    cookie.parse("foo=;bar=bar;foo=boo", {
+      multiValuedCookies: true,
+    })
+  );
+  assert.deepEqual(
+    { foo: ["%1", "boo", "bar"], bar: "bar" },
+    cookie.parse("foo=%1;bar=bar;foo=boo;foo=bar", {
+      multiValuedCookies: true,
+    })
+  );
+  assert.deepEqual(
+    { foo: "%1", bar: "bar" },
+    cookie.parse("foo=%1;bar=bar", {
+      multiValuedCookies: true,
+    })
+  );
+});