How to convert a string to a enum?
You can simply cast the string result as the Enum type:
$HealthStateResultEnum = [HealthState]$jsonResult
This will work whether $jsonResult
contains a string or value from the enum type.
Assuming you want to get the value__ of the enum:
PS> [Enum]::GetValues([HealthState])|? {$_ -eq $JSonresult}|Select @{n="Name";e={"$_"}},value__Name value__---- -------Ok 1
Or simply
PS> [int]([HealthState]$jsonResult)1