ConvertFrom-Json and Test-Json accept non-compliant/non-standard JSON - no way to strictly validate JSON

Summary of the new feature/enhancement

There does not seem to be any way to validate whether a JSON string is valid, which makes it impossible to use PowerShell to validate JSON before passing it to another application.

For example, the following JSON is invalid due to the trailing comma, but Test-Json still returns $true.

'{"hello": "world",}' | Test-Json

I propose adding a -Strict parameter to Test-Json for testing that the JSON string adheres strictly to the JSON specification.

Side note

I was very excited when I found the Test-Json cmdlet, but so far every use case it would have helped, it has not behaved as expected. See also #9560. If this cannot be implemented using the current library, please strongly consider using Json.NET instead of NJsonSchema.

[iSazonov]

.Net Core team actively works on new JSON API implementation to replace Json.Net. All new features will be in .Net Core. Open feature request issues in CoreFX repo if you want more features - we will get them.

[iSazonov]

For reference #18023