how to get back original file code after running production command in laravel mix

Are you concatenating the script files?

@TOKOIWESLEY - yes

have you tried

    npm run dev

In your config/app.php as look like below?

    'debug' => env('APP_DEBUG', true),

Yes

@MUNAZZIL - Tried with this also

Have you update npm

npm update

can you show in your blade.js files inside the <script>?

I had updated npm

As @munazzil pointed out, enable debug mode in the .env file APP_DEBUG=true and run npm run dev then go to the page where the error happens in your browser. Use the console tab on your browser Dev Tools to get info about the error(s) by refreshing the page. The error log will also give you a link to the line(s) of code responsible.

surely if theres an error in your JS - you should get the same error in local..? which means you should be able to debug in your local/staging servers.

@TOKOIWESLEY - When run npm dev and check for error in console log , its show unminified code and point also where is error occur ,but it show all code in single file (in my app.js is mix file). It don't show like glup which is previously used in laravel 5, there in console you know that the code is from which file , but this is not happening laravel 5.4

Use as like below in your main.blade.php or home.blade.php

<script src="{{ mix('js/app.js') }}"></script>
<link href="{{ mix('css/app.css') }}" rel="stylesheet" type="text/css">