Added the underscore node_module.

node_modules/underscore/modules/_createEscaper.js

@@ -0,0 +1,17 @@
+import keys from './keys.js';
+
+// Internal helper to generate functions for escaping and unescaping strings
+// to/from HTML interpolation.
+export default function createEscaper(map) {
+  var escaper = function(match) {
+    return map[match];
+  };
+  // Regexes for identifying a key that needs to be escaped.
+  var source = '(?:' + keys(map).join('|') + ')';
+  var testRegexp = RegExp(source);
+  var replaceRegexp = RegExp(source, 'g');
+  return function(string) {
+    string = string == null ? '' : '' + string;
+    return testRegexp.test(string) ? string.replace(replaceRegexp, escaper) : string;
+  };
+}