Problem installing npm and running it

[genesisbell]

When I try to install npm i get all these errors

npm WARN deprecated chokidar@2.1.8: Chokidar 2 will break on node v14+. Upgrade to chokidar 3 with 15x less dependencies.
npm WARN deprecated hoek@4.2.1: This version has been deprecated in accordance with the hapi support policy (hapi.im/support). Please upgrade to the latest version to get the best features, bug fixes, and security patches. If you are unable to upgrade at this time, paid support is available for older versions (hapi.im/commercial).
npm WARN deprecated fsevents@1.2.13: fsevents 1 will break on node v14+ and could be using insecure binaries. Upgrade to fsevents 2.
npm WARN deprecated resolve-url@0.2.1: https://github.com/lydell/resolve-url#deprecated
npm WARN deprecated urix@0.1.0: Please see https://github.com/lydell/urix#deprecated
npm ERR! Unexpected end of JSON input while parsing near '...mi47eBseEM9jHbyD9\nhp'

npm ERR! A complete log of this run can be found in:
npm ERR! C:**\AppData\Roaming\npm-cache_logs\2020-06-22T08_05_45_748Z-debug.log

and when I want to run it a get all of these

building-a-geospatial-app@0.0.1 start C:\Users\genesisbell\vis-academy\src\demos\building-a-geospatial-app\starting-code
webpack-dev-server --config ./webpack.config.js --mode development

'webpack-dev-server' is not recognized as an internal or external command,
operable program or batch file.
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! building-a-geospatial-app@0.0.1 start: webpack-dev-server --config ./webpack.config.js --mode development
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the building-a-geospatial-app@0.0.1 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm WARN Local package.json exists, but node_modules missing, did you mean to install?

npm ERR! A complete log of this run can be found in:
npm ERR! C:**\AppData\Roaming\npm-cache_logs\2020-06-22T08_02_50_642Z-debug.log