private/ConvertFrom-YamlFrontMatter.ps1
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function ConvertFrom-YamlFrontMatter { [CmdletBinding()] [OutputType([PSCustomObject])] param ( [Parameter(Mandatory = $true)] [System.IO.FileInfo]$InputFile ) $content = Get-Content $InputFile $startIndex = $null $endIndex = $null # YAML frontmatter is delimited by '---' for ($i = 0; $i -lt $content.Count; $i++) { if ($content[$i].Trim() -eq '---') { if ($null -eq $startIndex) { $startIndex = $i } else { $endIndex = $i; break } } } if ($null -eq $startIndex -or $null -eq $endIndex) { Write-Error 'Unable to locate frontmatter markers in the file.' return } # Extract the frontmatter lines (excluding the marker lines) $frontmatterLines = $content[($startIndex + 1)..($endIndex - 1)] $properties = @{} $currentKey = $null $inArray = $false $arrayValues = @() foreach ($line in $frontmatterLines) { $trimLine = $line.TrimEnd() if ($trimLine -match '^(?<key>[^:]+):\s*(?<value>.*)$') { # If we were collecting array items for the previous key, save them. if ($inArray -and $null -ne $currentKey) { $properties[$currentKey] = $arrayValues $arrayValues = @() $inArray = $false } $currentKey = $Matches['key'].Trim() $value = $Matches['value'].Trim() if ($value -eq "") { # No inline value; expect multi-line array items $inArray = $true } else { $properties[$currentKey] = Convert-FrontMatterValue $value } } elseif ($inArray -and $trimLine -match '^\s*-\s*(?<item>.+)$') { $item = $Matches['item'].Trim() $arrayValues += Convert-FrontMatterValue $item } } # If the last key was an array, add it to properties if ($inArray -and $null -ne $currentKey) { $properties[$currentKey] = $arrayValues } return [PSCustomObject]$properties } |