E:\angular2\projects2018\angularFlex>npm install

> node-sass@4.7.2 install E:\angular2\projects2018\angularFlex\node_modules\node-sass
> node scripts/install.js

module.js:471
    throw err;
    ^

Error: Cannot find module 'true-case-path'
    at Function.Module._resolveFilename (module.js:469:15)
    at Function.Module._load (module.js:417:25)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (E:\angular2\projects2018\angularFlex\node_modules\node-sass\lib\extensions.js:11:22)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)