Updated readme + extra config option

Author: matthisk

README.md

@@ -45,12 +45,21 @@ if (process.env.NODE_ENV === 'development') {
 }
 ```
 
+### Source Map Support
+
+Even though it is not desirable to run transpiled source code inside the
+node js runtime, you often do not escape the use of it because of Server Side
+Rendering applications. `debug-error-middleware` automatically supports sourcemaps. 
+This will result in stack traces that are easier to interpret. You can disable 
+source map support through a configuration option.
+
 ### Configuration
 
 The following configuration options are available:
 
 ```javascript
 {
   disabledForXHR: true // Disable the middleware for XHR requests
+  disableSourceMapSupport: false // Disables support for sourcemaps
 }
 ```

index.js

@@ -1,7 +1,8 @@
 'use strict';
 
 const defaultOptions = {
-  disabledForXHR: true
+  disabledForXHR: true,
+  disableSourceMapSupport: false,
 };
 
 module.exports.express = function stack(options) {

src/main.js

@@ -58,7 +58,7 @@ function trimResult(input) {
   return result;
 }
 
-function parseStack(error) {
+function parseStack(opts, error) {
   const stack = error.stack.split('\n').slice(1);
   const regex = /at ([\w.]+) \(([^:]+):(\d+):(\d+)\)/;
 
@@ -89,7 +89,7 @@ function parseStack(error) {
           }
           return result;
         })
-        .then(r => parseSourceMap(r))
+        .then(r => (opts.disableSourceMapSupport ? r : parseSourceMap(r)))
         .then(r => trimResult(r));
     })
   );
@@ -140,7 +140,7 @@ function getProcess() {
 }
 
 module.exports = function main(opts, error, req) {
-  return Promise.all([loadPrism(), parseStack(error)]).then(args => {
+  return Promise.all([loadPrism(), parseStack(opts, error)]).then(args => {
     const codemirror = args[0];
     const stack = args[1];
     // 3: Create config for Handlebars