[api] [fix] Safer Faker.fake call #310

  * Removes eval() call from pull request
  * eval() is not safe
  * Never was actually checked into main repo
  * Now uses JSON.parse and fn.apply()

lib/fake.js

@@ -32,7 +32,7 @@ function Fake (faker) {
     var method = token.replace('}}', '').replace('{{', '');
 
     // console.log('method', method)
-     
+
     // extract method parameters
     var regExp = /\(([^)]+)\)/;
     var matches = regExp.exec(method);
@@ -56,8 +56,22 @@ function Fake (faker) {
     // assign the function from the module.function namespace
     var fn = faker[parts[0]][parts[1]];
 
+    // If parameters are populated here, they are always going to be of string type
+    // since we might actually be dealing with an object or array,
+    // we always attempt to the parse the incoming parameters into JSON
+    var params;
+    // Note: we experience a small performance hit here due to JSON.parse try / catch
+    // If anyone actually needs to optimize this specific code path, please open a support issue on github
+    try {
+      params = JSON.parse(parameters)
+    } catch (err) {
+      // since JSON.parse threw an error, assume parameters was actually a string
+      params = parameters;
+    }
+
+    var result = fn.call(this, params);
+
     // replace the found tag with the returned fake value
-    eval('var result = fn(' + parameters + ');');
     res = str.replace('{{' + token + '}}', result);
 
     // return the response recursively until we are done finding all tags