Cannot read property 'length' of null

[IzaGz]

./node_modules/webpack-cli/bin/webpack.js migrate webpack.config.js 
? Migration output path not specified. Do you want to use your existing webpack configuration? Yes
 ✔ Reading webpack config
 ❯ Migrating config to newest version
   ✔ loadersTransform
   ✔ resolveTransform
   ✔ removeJsonLoaderTransform
   ✖ uglifyJsPluginTransform
     → Cannot read property 'length' of null
     loaderOptionsPluginTransform
     bannerPluginTransform
     extractTextPluginTransform
     noEmitOnErrorsPluginTransform
     removeDeprecatedPluginsTransform

 ✖ ︎Migration aborted due to some errors: 

{ TypeError: Cannot read property 'length' of null
    at NodePath.rootNode.find.forEach.node (/Users/z/project/node_modules/webpack-cli/lib/utils/ast-utils.js:78:16)
    at __paths.forEach (/Users/z/project/node_modules/jscodeshift/src/Collection.js:76:36)
    at Array.forEach (native)
    at Collection.forEach (/Users/z/project/node_modules/jscodeshift/src/Collection.js:75:18)
    at findPluginsArrayAndRemoveIfEmpty (/Users/z/project/node_modules/webpack-cli/lib/utils/ast-utils.js:71:58)
    at module.exports (/Users/z/project/node_modules/webpack-cli/lib/migrate/uglifyJsPlugin/uglifyJsPlugin.js:120:2)
    at Timeout.err [as _onTimeout] (/Users/z/project/node_modules/webpack-cli/lib/migrate/index.js:37:13)
    at ontimeout (timers.js:365:14)
    at tryOnTimeout (timers.js:237:5)
    at Timer.listOnTimeout (timers.js:207:5)
  context: 

[evenstensberg]

Hi @IzaGz , could you use the issue template that is provided next time? Which version are you on?

[evenstensberg]

Moved to #541

[IzaGz]

@ev1stensberg i was on 2.1.1 but got this error #541
then i moved to 1.2.0 and got this error with length

[evenstensberg]

Could you move to the latest version? It should be no problem for you

[IzaGz]

@ev1stensberg i use webpack 2 i am migrating from webpack 1 to 2
i see this library for migrationg from 1 to 2 only. But why i see this error?
webpack-cli@2.1.5 requires a peer of webpack@^4.0.0 but none was installed.

[evenstensberg]

What happens if you run the newest version? Any errors? Ignore those warnings for now

[IzaGz]

@ev1stensberg if i run with webpack-cli 3.0.8 i got error
#541
`node node_modules/webpack-cli/bin/cli.js migrate webpack.config.js
/Users/z/project/src/_mobile/node_modules/@webpack-cli/migrate/index.js:11
const { validate } = process.webpackModule;
^

TypeError: Cannot destructure property validate of 'undefined' or 'null'.
at Object. (/Users/z/project/src/_mobile/node_modules/@webpack-cli/migrate/index.js:11:30)
at Module._compile (/Users/z/project/src/_mobile/node_modules/v8-compile-cache/v8-compile-cache.js:178:30)
at Object.Module._extensions..js (module.js:663:10)
at Module.load (module.js:565:32)
at tryModuleLoad (module.js:505:12)
at Function.Module._load (module.js:497:3)
at Module.require (module.js:596:17)
at require (/Users/z/project/src/_mobile/node_modules/v8-compile-cache/v8-compile-cache.js:159:20)
at promptForInstallation (/Users/z/project/src/_mobile/node_modules/webpack-cli/bin/prompt-command.js:108:3)
at /Users/z/project/src/_mobile/node_modules/webpack-cli/bin/cli.js:45:37
`

[evenstensberg]

Try v.3.2 and up. Just upgrade to the latest, that's the easiest way to get the error gone.

[IzaGz]

@ev1stensberg but where can i found the list of versions? in the https://github.com/webpack/webpack-cli/releases page only 3.0.8 last
i tried npm i -S webpack-cli@latest - I thought this will install the latest version...
How could i now the real latest version?

[evenstensberg]

npm uninstall webpack-cli && npm install --save-dev webpack-cli@latest

[IzaGz]

@ev1stensberg it installs 3.0.8 version

[evenstensberg]

Could you check with version is the latest one in Npm? Try to install rhat. There's no breaking things CLI wise for you to be stuck at updating the dependency

[mayanksingh0821]

Issue is still present with webpack-cli 3.1.2, why is this issue closed?

[ematipico]

File a new issue please. The source of the problem could be different