json sketch

Pwsh/Modules/Text.Json/sketch/dynamicJsonClass--iter2.ps1

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+using namespace System.Collections.Generic
+using namespace System.IO
+using namespace System.Linq
+using namespace System.Text
+using namespace System.Text.Json
+using namespace System.Text.Json.Serialization
+$assembly = Add-type -AssemblyName System.Text.Json -PassThru -ea 'stop'
+pushd $PSScriptRoot
+function AutoJson {
+    <#
+    .SYNOPSIS
+        Try one of the automatic methods
+    .notes
+        [System.Text.Json.JsonSerializer] has a ton of overloads
+    .LINK
+        https://docs.microsoft.com/en-us/dotnet/api/system.text.json.jsonserializer?view=net-8.0#methods
+    #>
+    param(
+        [Alias('InObj', 'In')]
+        [object] $Object,
+
+        # Without a type, it falls back to GetType()
+        [Alias('Tinfo', 'T')]
+        [type] $TypeInfo
+    )
+    if(-not $TypeInfo ) { $TypeInfo = $Object.GetType() }
+    [JsonSerializer]::Serialize( <# value: #> $Object, <# tinfo #> $TypeInfo )
+}
+# [Serialization.JsonIgnore(Condition = [Serialization.JsonIgnoreCondition]::Always)]
+
+# [JsonSerializer]::Serialize( <# value: #> $CastObj, <# jsonTypeInfo: #> [Forecast])
+# [JsonSerializer]::Serialize( <# value: #> $CastObj, $CastObj.GetType() )
+
+class SimpleProcess {
+    [string]$Name
+    [string]$CommandLine
+
+    # example kind1: something that should never serialize
+    [Serialization.JsonIgnoreAttribute()]
+    [Diagnostics.ProcessModuleCollection] $Modules
+
+    # some property that can be blank
+    # example kind2: serialize when not null
+    [JsonIgnoreAttribute( Condition = [JsonIgnoreCondition]::WhenWritingNull) ]
+    [string]$MainWindowTitle = ''
+
+    SimpleProcess ( ) {
+    }
+    SimpleProcess ( [object]$Other ) {
+        # $This.Name            = ($Other)?.Name ?? ''
+        # $This.CommandLine     = ($Other)?.CommandLine ?? ''
+        # $this.MainWindowTitle = ($Other)?.MainWindowTitle ?? ''
+        # $This.Modules         = ($Other)?.Modules
+        $WantedProps = [Linq.Enumerable]::Intersect(
+            [string[]] $This.PSObject.Properties.Name,
+            [string[]] $Other.PSObject.Properties.Name )
+
+        foreach($PropName in $WantedProps) {
+            $This.$PropName = $Other.$PropName
+        }
+    }
+}
+
+$pslist = [SimpleProcess[]] @(
+    Get-Process
+        | Select-First -first 3
+    Get-Process
+        | ?{ $_.MainWindowTitle.length -gt 0 }
+        | select -first 1
+)
+h1 'should only serialize .MaybeData for one result'
+AutoJson $pslist| jq
+
+<#
+other ways to instantiate object
+#>
+[SimpleProcess] @(get-process | select-object -first 1 )
+# return
+[List[Object]] $Records = @(
+    # class coerce from an object
+    [SimpleProcess] (get-process pwsh | Select-Object -First 1)
+
+    # explicit ctor
+    [SimpleProcess]::new()
+
+    # automatic if parameterless c-tor:
+    [SimpleProcess] @{}
+
+    # a similar variation
+    $One = Get-Process 'pwsh' | Select -first 1
+    [SimpleProcess] $One
+)
+
+$records | ft -auto
+
+# neat, it works without extra work
+AutoJson $Records
+
+<#
+example output:
+[{"Name":"pwsh","CommandLine":"\u0022C:\\Program Files\\PowerShell\\7\\pwsh.exe\u0022 -WorkingDirectory ~"},{"Name":null,"CommandLine":null},{"Name":"","CommandLine":""},{"Name":"pwsh","CommandLine":"\u0022C:\\Program Files\\PowerShell\\7\\pwsh.exe\u0022 -WorkingDirectory ~"}]
+
+- [c# Text.Json intro](https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/how-to)
+#>
+
+AutoJson $pslist[-1]
+AutoJson $pslist[0]
+<#
+Outputs:
+{"Name":"ApplicationFrameHost","CommandLine":"C:\\WINDOWS\\system32\\ApplicationFrameHost.exe -Embedding","MainWindowTitle":"Settings"}
+{"Name":"AppleMobileDeviceService","CommandLine":"","MainWindowTitle":""}
+#>