Error: Cannot find module 'webpack'

[softmarshmallow]

after following tutorial on medium,

this crab happens

internal/modules/cjs/loader.js:589
    throw err;
    ^

Error: Cannot find module 'webpack'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:587:15)
    at Function.Module._load (internal/modules/cjs/loader.js:513:25)
    at Module.require (internal/modules/cjs/loader.js:643:17)
    at require (internal/modules/cjs/helpers.js:22:18)
    at Object.<anonymous> (/Users/softmarshmallow/Desktop/launchers-react-app/packages/app/scripts/start.js:20:17)
    at Module._compile (internal/modules/cjs/loader.js:707:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:718:10)
    at Module.load (internal/modules/cjs/loader.js:605:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:544:12)
    at Function.Module._load (internal/modules/cjs/loader.js:536:3)
error An unexpected error occurred: "Command failed.
Exit code: 1
Command: sh
Arguments: -c node scripts/start.js
Directory: /Users/softmarshmallow/Desktop/launchers-react-app/packages/app
Output:
".
info If you think this is a bug, please open a bug report with the information provided in "/Users/softmarshmallow/Desktop/launchers-react-app/packages/app/yarn-error.log".
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[F1LT3R]

https://github.com/F1LT3R/cra-workspaces-poc