powershell convert the date property to string when using ConvertTo-Json - powershell

Question

I'd like to get all Hyper-V VM information from Get-VM cmdlet as below:
Get-Vm | Select-Object * | ConvertTo-Json
Where the CreationTime in each VM dictionary looks like \/Date(-11644473600000)\/", in the output
How can I make it look like this format 2017/11/29 16:09:00 in the output json?
When I guess it is the number of Epoch timestamp, I found it sometimes a negative number.
I found some articles taking about this issue which take Get-Date for example, but in my case it is a property in Get-VM that I am not sure if a faster way to convert the date property without long script to parse the output.

Answer 1

To select a Property based on an user defined Expression one can define them in Select-Object the following way:
Get-VM | Select-Object -Property #{Name="ReadableCreationTime"; Expression={Get-Date $_.CreationTime}}, *
This selects the user defined property ReadableCreationTime and all other properties (*).
Now, you want to exclude the original CreationTime as it is a) hard to read and b) redundant to ReadableCreationTime. This can be done using the -ExcludeProperty parameter:
Get-VM | Select-Object -Property #{Name="ReadableCreationTime"; Expression={Get-Date $_.CreationTime}}, * -ExcludeProperty CreationTime
...And pipe the result to ConvertTo-Json
Keep in mind that while reading the resulting json, you have to parse the date, because it is just a string, not a valid Date value.