json-flattening.ps1

# 1. Configuration
$jsonInputPath = "C:\path\to\your\input.json"
$outputPath = "C:\path\to\your\output.txt"

# 2. Function to recursively flatten objects and arrays
function Flatten-JsonObject ($Object, $Prefix = "") {
    $results = [ordered]@{}

    foreach ($property in $Object.PSObject.Properties) {
        # Construct the base key name (e.g., Person.Children)
        $name = if ($Prefix -eq "") { $property.Name } else { "$Prefix.$($property.Name)" }
        $value = $property.Value

        # CASE 1: The value is a nested Object
        if ($value -is [System.Management.Automation.PSCustomObject]) {
            $subResults = Flatten-JsonObject -Object $value -Prefix $name
            foreach ($key in $subResults.Keys) { $results[$key] = $subResults[$key] }
        } 
        
        # CASE 2: The value is an Array/Collection
        elseif ($value -is [System.Collections.IEnumerable] -and $value -isnot [string]) {
            $index = 0
            foreach ($item in $value) {
                $arrayName = "$name[$index]"
                
                # If array contains objects, recurse into them
                if ($item -is [System.Management.Automation.PSCustomObject]) {
                    $subResults = Flatten-JsonObject -Object $item -Prefix $arrayName
                    foreach ($key in $subResults.Keys) { $results[$key] = $subResults[$key] }
                } else {
                    # If array contains simple values (strings/ints)
                    $results[$arrayName] = $item
                }
                $index++
            }
        }
        
        # CASE 3: The value is a "Leaf" (String, Int, etc.)
        else {
            $results[$name] = $value
        }
    }
    return $results
}

# 3. Execution
try {
    if (Test-Path $jsonInputPath) {
        $json = Get-Content -Raw -Path $jsonInputPath | ConvertFrom-Json
        $flattened = Flatten-JsonObject -Object $json
        
        # Format as "Key: Value"
        $outputStrings = $flattened.GetEnumerator() | ForEach-Object { "$($_.Key): $($_.Value)" }
        
        $outputStrings | Out-File -FilePath $outputPath -Encoding utf8
        $outputStrings # Display result
    }
} catch {
    Write-Error "Error: $($_.Exception.Message)"
}