Get-RoadmapData.ps1

#region Settings and variables
$dataFolder = 'data'
$versionFolder = Join-Path $dataFolder 'versions'
$roadmapRSSUri = 'https://www.microsoft.com/en-us/microsoft-365/RoadmapFeatureRSS/'
$timestamp = Get-Date -Format 'o'
#endregion Settings and variables

#region Functions
function ConvertRSSToFile {
	param(
		[Parameter(Mandatory = $true,
			ValueFromPipeline = $true)]
		[Object]
		$InputObject
	)
	process {
		$matches = $null
		$publicPreviewDate = $null
		$GADate = $null
		if ($InputObject.description -match '(?: *<br>Preview date: )([\w ]+)') {
			$publicPreviewDate = $matches.1
			$InputObject.description = $InputObject.description.Replace($matches.0, '')
		}
		if ($InputObject.description -match '(?: *<br>GA date: )([\w ]+)') {
			$GADate = $matches.1
			$InputObject.description = $InputObject.description.Replace($matches.0, '')
		}

		$objProperties = [ordered]@{
			'guid'                             = $InputObject.guid.'#text'
			'link'                             = $InputObject.link
			'category'                         = $InputObject.category | Sort-Object
			'title'                            = $InputObject.title
			'description'                      = $InputObject.description
			'pubDate'                          = $InputObject.pubDate
			'updated'                          = $InputObject.updated
			'publicDisclosureAvailabilityDate' = $GADate
			'publicPreviewDate'                = $publicPreviewDate
		}
		$processedObj = [PSCustomObject]$objProperties

		ConvertTo-Json -InputObject $processedObj
	}
}
#endregion Functions

#region Processing
Write-Host 'Script starting'
$res = Invoke-RestMethod $roadmapRSSUri

if (-not (Test-Path $dataFolder)) {
	New-Item -ItemType Directory $dataFolder
	Write-Host "Creating $dataFolder folder"
}

foreach ($entry in $res) {
	<#
	$entry = $res[0]
	#>
	# Generate filename
	$fileName = $entry.guid.'#text'
	$jsonEntry = $entry | ConvertRSSToFile
	$outFilePath = Join-Path -Path $dataFolder -ChildPath "$fileName.json"

	# Save previous version
	$isNew = -not (Test-Path $outFilePath)
	if (-not $isNew) {
		$previousData = Get-Content $outFilePath | ConvertFrom-Json
	}

	# Save to file
	$jsonEntry | Out-File -FilePath $outFilePath -Force

	# Extract changes
	$currentData = $jsonEntry | ConvertFrom-Json
	if (Compare-Object $currentData.PSObject.Properties $previousData.PSObject.Properties) {
		# If there are differences
		$versionNumber = 0
		$versionEntryFolder = Join-Path $versionFolder $fileName
		if (-not (Test-Path $versionEntryFolder)) {
			New-Item -ItemType Directory $versionEntryFolder
		}
		do {
			$versionNumber++
			$versionFile = Join-Path $versionEntryFolder "v$($versionNumber.ToString('0000')).json"
		} until (-not (Test-Path $versionFile))
		# Save differences to file
		$fullContentObj =  $currentData | Select-Object @{name="timestamp";expression={$timestamp}},* 
		$fullContentObj | ConvertTo-Json | Out-File $versionFile -Force
	}
}
Write-Host 'Script finished'
#endregion Processing