Problems to test

[enrutador]

Hi
I like to probe your test solution , but i have some errors:

# npm run dev

> dapp-sample-contacts@1.0.0 dev /usr/local/src/dapp-example-contacts
> webpack-dev-server --inline --progress --config build/webpack.dev.conf.js

internal/modules/cjs/loader.js:583
    throw err;
    ^

Error: Cannot find module 'webpack-cli/bin/config-yargs'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:581:15)
    at Function.Module._load (internal/modules/cjs/loader.js:507:25)
    at Module.require (internal/modules/cjs/loader.js:637:17)
    at require (internal/modules/cjs/helpers.js:22:18)
    at Object.<anonymous> (/usr/local/src/dapp-example-contacts/node_modules/webpack-dev-server/bin/webpack-dev-server.js:84:1)
    at Module._compile (internal/modules/cjs/loader.js:689:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
    at Module.load (internal/modules/cjs/loader.js:599:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
    at Function.Module._load (internal/modules/cjs/loader.js:530:3)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! dapp-sample-contacts@1.0.0 dev: `webpack-dev-server --inline --progress --config build/webpack.dev.conf.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the dapp-sample-contacts@1.0.0 dev 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!     /root/.npm/_logs/2019-10-02T11_21_23_965Z-debug.log

I installed the webpack with : npm i -D g webpack-cli

But the error is the same (attach log)

# cat /root/.npm/_logs/2019-10-02T11_23_41_173Z-debug.log
0 info it worked if it ends with ok
1 verbose cli [ '/usr/bin/node', '/usr/local/bin/npm', 'run', 'dev' ]
2 info using npm@6.9.0
3 info using node@v10.15.2
4 verbose run-script [ 'predev', 'dev', 'postdev' ]
5 info lifecycle dapp-sample-contacts@1.0.0~predev: dapp-sample-contacts@1.0.0
6 info lifecycle dapp-sample-contacts@1.0.0~dev: dapp-sample-contacts@1.0.0
7 verbose lifecycle dapp-sample-contacts@1.0.0~dev: unsafe-perm in lifecycle true
8 verbose lifecycle dapp-sample-contacts@1.0.0~dev: PATH: /usr/local/lib/node_modules/npm/node_modules/npm-lifecycle/node-gyp-bin:/usr/local/src/dapp-example-contacts/node_modules/.bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/go-1.12/bin:/root/go/bin
9 verbose lifecycle dapp-sample-contacts@1.0.0~dev: CWD: /usr/local/src/dapp-example-contacts
10 silly lifecycle dapp-sample-contacts@1.0.0~dev: Args: [ '-c',
10 silly lifecycle   'webpack-dev-server --inline --progress --config build/webpack.dev.conf.js' ]
11 silly lifecycle dapp-sample-contacts@1.0.0~dev: Returned: code: 1  signal: null
12 info lifecycle dapp-sample-contacts@1.0.0~dev: Failed to exec dev script
13 verbose stack Error: dapp-sample-contacts@1.0.0 dev: `webpack-dev-server --inline --progress --config build/webpack.dev.conf.js`
13 verbose stack Exit status 1
13 verbose stack     at EventEmitter.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/npm-lifecycle/index.js:301:16)
13 verbose stack     at EventEmitter.emit (events.js:189:13)
13 verbose stack     at ChildProcess.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/npm-lifecycle/lib/spawn.js:55:14)
13 verbose stack     at ChildProcess.emit (events.js:189:13)
13 verbose stack     at maybeClose (internal/child_process.js:970:16)
13 verbose stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:259:5)
14 verbose pkgid dapp-sample-contacts@1.0.0
15 verbose cwd /usr/local/src/dapp-example-contacts
16 verbose Linux 5.0.0-20-generic
17 verbose argv "/usr/bin/node" "/usr/local/bin/npm" "run" "dev"
18 verbose node v10.15.2
19 verbose npm  v6.9.0
20 error code ELIFECYCLE
21 error errno 1
22 error dapp-sample-contacts@1.0.0 dev: `webpack-dev-server --inline --progress --config build/webpack.dev.conf.js`
22 error Exit status 1
23 error Failed at the dapp-sample-contacts@1.0.0 dev script.
23 error This is probably not a problem with npm. There is likely additional logging output above.
24 verbose exit [ 1, true ]

The error is due to the webpack version, or some code error?
Thank you