It exists

Author: Rory Fitzpatrick

.gitignore

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+node_modules

LICENSE

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+Copyright (c) 2012-2014, Walmart and other contributors.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+    * The names of any contributors may not be used to endorse or promote
+      products derived from this software without specific prior written
+      permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+                                  *   *   *

index.js

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+module.exports = function parseCacheControl(field) {
+
+  /*
+    Cache-Control   = 1#cache-directive
+    cache-directive = token [ "=" ( token / quoted-string ) ]
+    token           = [^\x00-\x20\(\)<>@\,;\:\\"\/\[\]\?\=\{\}\x7F]+
+    quoted-string   = "(?:[^"\\]|\\.)*"
+  */
+
+  //                             1: directive                                        =   2: token                                              3: quoted-string
+  var regex = /(?:^|(?:\s*\,\s*))([^\x00-\x20\(\)<>@\,;\:\\"\/\[\]\?\=\{\}\x7F]+)(?:\=(?:([^\x00-\x20\(\)<>@\,;\:\\"\/\[\]\?\=\{\}\x7F]+)|(?:\"((?:[^"\\]|\\.)*)\")))?/g;
+
+  var header = {};
+  var err = field.replace(regex, function($0, $1, $2, $3) {
+    var value = $2 || $3;
+    header[$1] = value ? value.toLowerCase() : true;
+    return '';
+  });
+
+  if (header['max-age']) {
+    try {
+      var maxAge = parseInt(header['max-age'], 10);
+      if (isNaN(maxAge)) {
+        return null;
+      }
+
+      header['max-age'] = maxAge;
+    }
+    catch (err) { }
+  }
+
+  return (err ? null : header);
+};

package.json

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+{
+  "name": "parse-cache-control",
+  "version": "1.0.0",
+  "description": "Parse Cache-Control headers.",
+  "main": "index.js",
+  "scripts": {
+    "test": "tape test.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/roryf/parse-cache-control.git"
+  },
+  "devDependencies": {
+    "tape": "^3.5.0"
+  },
+  "licenses": [
+    {
+      "type": "BSD",
+      "url": "http://github.com/hapijs/wreck/raw/master/LICENSE"
+    }
+  ]
+}

test.js

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+var test = require('tape');
+var parseCacheControl = require('./index');
+
+test('parseCacheControl', function (t) {
+  var header = parseCacheControl('must-revalidate, max-age=3600');
+  t.ok(header);
+  t.equal(header['must-revalidate'], true);
+  t.equal(header['max-age'], 3600);
+
+  header = parseCacheControl('must-revalidate, max-age="3600"');
+  t.ok(header);
+  t.equal(header['must-revalidate'], true);
+  t.equal(header['max-age'], 3600);
+
+  header = parseCacheControl('must-revalidate, b =3600');
+  t.notOk(header);
+
+  header = parseCacheControl('must-revalidate, max-age=a3600');
+  t.notOk(header);
+
+  t.end();
+});