NPM troubleshooting documentation

[JamesNK]

I ran into an NPM error while setting up SignalR.

Many devs discussing it, plus the solution is here - npm/npm#10826

Full error message:

Restoring NPM modules
npm WARN [email protected] No repository field.

added 105 packages in 3.556s
npm ERR! path C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json.114822873
npm ERR! code EPERM
npm ERR! errno -4048
npm ERR! syscall rename
EXEC : npm ERR! error : EPERM: operation not permitted, rename 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json.114822873' -> 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json' [C:\Users\James.dotnet\buildtools\korebuild\2.1.0-preview2-15721\KoreBuild.proj]
EXEC : npm ERR! { error : EPERM: operation not permitted, rename 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json.114822873' -> 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json' [C:\Users\James.dotnet\buildtools\korebuild\2.1.0-preview2-15721\KoreBuild.proj]
npm ERR! cause:
EXEC : npm ERR! { error : EPERM: operation not permitted, rename 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json.114822873' -> 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json' [C:\Users\James.dotnet\buildtools\korebuild\2.1.0-preview2-15721\KoreBuild.proj]
npm ERR! errno: -4048,
npm ERR! code: 'EPERM',
npm ERR! syscall: 'rename',
npm ERR! path: 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json.114822873',
npm ERR! dest: 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json' },
npm ERR! stack: 'Error: EPERM: operation not permitted, rename 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json.114822873' -> 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json'',
npm ERR! errno: -4048,
npm ERR! code: 'EPERM',
npm ERR! syscall: 'rename',
npm ERR! path: 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json.114822873',
npm ERR! dest: 'C:\Development\Source\SignalR\client-ts\FunctionalTests\node_modules\json-schema-traverse\package.json',
npm ERR! parent: 'functionaltests' }
npm ERR!
npm ERR! Please try running this command again as root/Administrator.

(I was already logged in as an administrator account so that part of the error message was no help)

[analogrelay]

Mac Failures are due to https://github.com/dotnet/corefx/issues/27571#issuecomment-370088975. Go ahead and "Squash and Merge" (our preferred merge strategy).