npm run watch Error in Cannot read property of 'map' undefined

Question

Problem: Running the command npm run watch throws and error

54% building 35/41 modules 6 active /app/docroot/themes/custom/mytheme/node_modules/css-loader/index.js??ref--10-2!/app/docroot/themes/custom/mytheme/node_modules/postcss-loader/src/index.js??postcss5!/app/docroot/themes
 ERROR  Failed to compile with 1 errors          1:25:50 AM

 error 

Cannot read property 'map' of undefined

 15 assets

ERROR in Cannot read property 'map' of undefined
[Browsersync] Proxying: https://ps.lndo.site

The Error happens only when the following code is included in my webpack.mix.js file:

mix.imagemin({
  patterns: [{
    from: '**/*.{png,gif,jpg,jpeg,svg}',
    to: 'images/',
    context: 'src/images/'
  }, {
    from: '**/*.{png,gif,jpg,jpeg,svg}',
    to: 'images/',
    context: 'src/components/'
  }]
  });

Removing the above snippet removes the error but the previous developers on this project had this for a reason.

I recently updated due to security vulnerabilities and managed to debug a different issue that Copy Plugin introduced a breaking change (already updated in the code above). However I am unsure that I have all of the configuration correct.

This I have tried: From the command line

rm -rf node_modules
rm package.lock
npm cache clean --force
npm install

These are the packages in package.json current as of August 27, 2020

"devDependencies": {
    "bootstrap": "^4.3.1",
    "browser-sync": "^2.26.12",
    "browser-sync-webpack-plugin": "^2.2.2",
    "copy-webpack-plugin": "^6.0.3",
    "cross-env": "^7.0.2",
    "husky": "^4.2.5",
    "imagemin-webpack-plugin": "^2.4.2",
    "jquery": "^3.5.1",
    "laravel-mix": "^5.0.4",
    "laravel-mix-imagemin": "^1.0.3",
    "popper.js": "^1.16.1",
    "pretty-quick": "^2.0.1",
    "resolve-url-loader": "^3.1.1",
    "sass": "^1.26.10",
    "sass-loader": "^8.0.2",
    "vue-template-compiler": "^2.6.11"
  },
"dependencies": {
    "throttle-debounce": "^2.3.0"
  }

The packages updated were the following

    "browser-sync": "^2.26.7",
    "copy-webpack-plugin": "^5.1.1",
    "husky": "^4.2.3",
    "jquery": "^3.5.0",
    "sass": "^1.26.3",

    "throttle-debounce": "^2.1.0"

Answer 1

To me this looks like a bug in the laravel-mix-imagemin plugin. Its NPM page says that "The patterns parameter is automatically converted to an array". But this doesn't comply with the copy-webpack-plugin^6 you are using (which is used under the hood by laravel-mix-imagemin), as version 6 doesn't accept an array anymore. (Too bad the laravel-mix-imagemin plugin doesn't list its dependencies and their versions properly ...)

BTW: I had basically the same issue, and the error message you get is a catastrophe.

Answer 2

Did not find a great answer, for now just removed imagemin configuration from webpack mix. Fixes the compile issue but does not resolve my original question.

Answer 3

You might be having a problem respect of the version of webpack. This is the best guess I can make. If this code worked before, then this could be a possibility.