Validate Schema from PowerShell

validate-schema.ps1

$ErrorActionPreference = "Stop"

$NewtonsoftJsonPath = Resolve-Path -Path "bin\Newtonsoft.Json.dll"
$NewtonsoftJsonSchemaPath = Resolve-Path -Path "bin\Newtonsoft.Json.Schema.dll"

Add-Type -Path $NewtonsoftJsonPath
Add-Type -Path $NewtonsoftJsonSchemaPath

$source = @'
    public class Validator
    {
        public static System.Collections.Generic.IList<string> Validate(Newtonsoft.Json.Linq.JToken token, Newtonsoft.Json.Schema.JSchema schema)
        {
            System.Collections.Generic.IList<string> messages;
            Newtonsoft.Json.Schema.SchemaExtensions.IsValid(token, schema, out messages);

            return messages;
        }
    }
'@
Add-Type -TypeDefinition $source -ReferencedAssemblies $NewtonsoftJsonPath,$NewtonsoftJsonSchemaPath

$Json = @'
{"prop1":"value"}
'@

$SchemaJson = @'
{"type":"array"}
'@

write-host "=========================" -foregroundcolor "white"
write-host "Json.NET Schema Validator" -foregroundcolor "white"
write-host "=========================" -foregroundcolor "white"
write-host
write-host "Json: $Json"
write-host "SchemaJson: $SchemaJson"

$Token = [Newtonsoft.Json.Linq.JToken]::Parse($Json)
$Schema = [Newtonsoft.Json.Schema.JSchema]::Parse($SchemaJson)

$ErrorMessages = [Validator]::Validate($Token, $Schema)
$IsValid = $ErrorMessages.Count -eq 0

write-host "Schema is valid: $IsValid" -foregroundcolor "white"

foreach ($ErrorMessage in $ErrorMessages) {
    write-host $ErrorMessage -foregroundcolor "red"
}

write-host

Unblocking the zip file solved initial problems for me as well, thanks ChristoperGrossert!

For some reason it does not work in vscode, however it does work in command prompt and ISE with no code changes.
You can do the same thing with the following lines:

            $token = [Newtonsoft.Json.Linq.JToken]::Parse( $Json )
            $schemaObj = [Newtonsoft.Json.Schema.JSchema]::Parse( $Schema )
            $errorMessages = New-Object -TypeName System.Collections.Generic.List[string]
            $result = [Newtonsoft.Json.Schema.SchemaExtensions]::IsValid( $token, $schemaObj, [ref] $errorMessages )

            if ( $errorMessages.Count ) {
                $result = $false
                $errorMessages | Write-Output
            }

Interrogate $result for your success or failure. I encapsulated this into a cmdlet to make it more portable.

After playing with it a bit, I got this to work in vscode:
Leaving the json and schema as strings resolved the type mismatch errors

            $moduleRootPath = Split-Path -Path ( Split-Path -Path $PSCommandPath -Parent ) -Parent
            Add-Type -Path "$moduleRootPath\bin\Newtonsoft.Json.dll"
            Add-Type -Path "$moduleRootPath\bin\Newtonsoft.Json.Schema.dll"

            $result = [Newtonsoft.Json.Schema.SchemaExtensions]::IsValid( $json, $schema, [ref] $errorMessages )

            if ( -not $result -or $errorMessages.Count ) {
                $result = $false
                $errorMessages | Write-Error
            }