Error building package

[ssshojaei]

➜ npm run package

> locky@0.0.1 package /home/saleh/Projects/open_sources/locky/locky_desktop
> npm run build


> locky@0.0.1 build /home/saleh/Projects/open_sources/locky/locky_desktop
> cross-env NODE_ENV=production webpack --config webpack.build.config.js --mode production

Hash: 9f5a6cf59b0e19e4ddc5
Version: webpack 4.44.0
Time: 4591ms
Built at: 07/29/2020 8:57:26 PM
 2 assets
Entrypoint main = bundle.css main.js

ERROR in unknown: Unexpected token (22748:6)
npm ERR! code ELIFECYCLE
npm ERR! errno 2
npm ERR! locky@0.0.1 build: `cross-env NODE_ENV=production webpack --config webpack.build.config.js --mode production`
npm ERR! Exit status 2
npm ERR! 
npm ERR! Failed at the locky@0.0.1 build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/saleh/.npm/_logs/2020-07-29T16_27_26_936Z-debug.log
npm ERR! code ELIFECYCLE
npm ERR! errno 2
npm ERR! locky@0.0.1 package: `npm run build`
npm ERR! Exit status 2
npm ERR! 
npm ERR! Failed at the locky@0.0.1 package script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/saleh/.npm/_logs/2020-07-29T16_27_27_111Z-debug.log

[alexdevero]

@ssshojaei I tried running npm run build and the app was build successfully.

$ npm run build                                                                              
                                                                                             
> electron-react-webpack-boilerplate@1.12.1 build X:\temp\electron-react-webpack-boilerplate                                      
> cross-env NODE_ENV=production webpack --config webpack.build.config.js --mode production   
                                                                                             
Hash: fd3feecde88d37ba9244                                                                   
Version: webpack 4.44.0                                                                      
Time: 9760ms                                                                                 
Built at: 30. 07. 2020 8:03:19                                                               
     Asset       Size  Chunks             Chunk Names                                        
bundle.css  478 bytes       0  [emitted]  main                                               
index.html  241 bytes          [emitted]                                                     
   main.js    128 KiB       0  [emitted]  main                                               
Entrypoint main = bundle.css main.js                                                         

Try this:

1. Delete node_modules folder and yarn.lock file (or package-lock.json) and re-install dependencies. Then, try running npm run build again.
2. Ensure your js or css don't contain any syntax errors.