Это исправило мою проблему
я есть что-то вроде этого:
WARNING in C:/Data/.../letsTest.jsx
There are multiple modules with names that only differ in casing.
This can lead to unexpected behavior when compiling on a filesystem with other case-semantic.
Use equal casing. Compare these module identifiers:
* C:\Data\...\node_modules\babel-loader\lib\index.js?presets[]=es2015&presets[]=react&presets[]=stage-0&presets[]=stage-2!C:\Data\...\letsTest.jsx
Used by 4 module(s), i. e.
multi C:/Data/Doc/13/13080801/LetsTest/letsTest.jsx
* C:\Data\...\node_modules\babel-loader\lib\index.js?presets[]=es2015&presets[]=react&presets[]=stage-0&presets[]=stage-2!c:\Data\...\letsTest.jsx
Used by 1 module(s), i. e.
C:\Data\...\node_modules\babel-loader\lib\index.js?presets[]=es2015&presets[]=react&presets[]=stage-0&presets[]=stage-2!C:\Data\...\r1HeadLearning.js
В чем проблема?