fix: remove ts mapping if loader present

fixes #2083

lib/config/defaults.js

@@ -1,7 +1,7 @@
 var ignoreRoot = require('ignore-by-default').directories();
 
 // default options for config.options
-module.exports = {
+const defaults = {
   restartable: 'rs',
   colours: true,
   execMap: {
@@ -12,7 +12,7 @@ module.exports = {
     // compatible with linux, mac and windows, or make the default.js
     // dynamically append the `.cmd` for node based utilities
   },
-  ignoreRoot: ignoreRoot.map(_ => `**/${_}/**`),
+  ignoreRoot: ignoreRoot.map((_) => `**/${_}/**`),
   watch: ['*.*'],
   stdin: true,
   runOnChangeOnly: false,
@@ -22,7 +22,11 @@ module.exports = {
   // but also includes stderr. If this is false, data is still dispatched via
   // nodemon.on('stdout/stderr')
   stdout: true,
-  watchOptions: {
-
-  },
+  watchOptions: {},
 };
+
+if ((process.env.NODE_OPTIONS || '').includes('--loader')) {
+  delete defaults.execMap.ts;
+}
+
+module.exports = defaults;