Replacing util.format with compat.format to fix Issue#3 and have node…

… < 5.4 compatibility

lib/compat.js

@@ -0,0 +1,24 @@
+//var format = require('util').format;
+
+/**
+ * Weak version of util.format supports only %s placeholders.
+ * Fixes Issue#3 compatibility with node < 5.4
+ */
+exports.format = function (fmt, args) {
+  if (fmt.indexOf('%d') != -1 ||
+      fmt.indexOf('%j') != -1) {
+    throw "This format only supports %s placeholders";
+  }
+  if (typeof arguments[0] != 'string') {
+    throw "First argument to format, must be a format string";
+  }
+  var i = 0;
+  var params = arguments;
+  return fmt.replace(/%s/g, function () {
+    i++;
+    if (params[i] === undefined) {
+      throw "Number of arguments didn't match format placeholders.";
+    }
+    return params[i];
+  });
+}

lib/connect-cachify.js

@@ -3,7 +3,7 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 var crypto = require('crypto'),
-    format = require('util').format,
+    format = require('./compat').format,
     fs = require('fs'),
     path = require('path'),
     und = require('underscore');

package.json

@@ -3,7 +3,7 @@
   "name": "connect-cachify",
   "description": "Connect middleware to provide easy frontend caching.",
   "keywords": ["cache", "HTTP", "expires", "asset", "max-age", "caching"],
-  "version": "0.0.2",
+  "version": "0.0.3",
   "homepage": "http://github.com/mozilla/connect-cachify",
   "repository": {
     "type": "git",

test/compat-test.js

@@ -0,0 +1,26 @@
+var compat   = require('../lib/compat'),
+    format   = compat.format,
+    nodeunit = require('nodeunit');
+
+exports.format = nodeunit.testCase({
+  "typical format": function (test) {
+    test.equal(format("/%s%s", "foo", "/bar"), "/foo/bar");
+    test.equal(format("%s/%s", "foo", "bar"), "foo/bar");
+    test.equal(format("%s", "foo"), "foo");
+    test.equal(format("ID#%s", 32432), "ID#32432");
+    test.equal(format("foo"), "foo");
+    test.done();
+  },
+  "programmer error": function (test) {
+    test.throws(function () {
+      format(1, "foo", "/bar");
+    });
+    test.throws(function () {
+      format("%d/%d", 1, 2);
+    });
+    test.throws(function () {
+      format("%s/%s");
+    });
+    test.done();
+  }
+});