Private/Format-Json.ps1

function Format-Json
{
    <#
    .SYNOPSIS
        Prettifies JSON output.
    .DESCRIPTION
        Reformats a JSON string so the output looks better than what ConvertTo-Json outputs.
    .PARAMETER Json
        Required: [string] The JSON text to prettify.
    .PARAMETER Minify
        Optional: Returns the json string compressed.
    .PARAMETER Indentation
        Optional: The number of spaces (1..1024) to use for indentation. Defaults to 4.
    .PARAMETER AsArray
        Optional: If set, the output will be in the form of a string array, otherwise a single string is output.
    .EXAMPLE
        $json | ConvertTo-Json | Format-Json -Indentation 2
    #>

    [CmdletBinding(DefaultParameterSetName = 'Prettify')]
    Param(
        [Parameter(Mandatory = $true, Position = 0, ValueFromPipeline = $true)]
        [string]$Json,

        [Parameter(ParameterSetName = 'Minify')]
        [switch]$Minify,

        [Parameter(ParameterSetName = 'Prettify')]
        [ValidateRange(1, 1024)]
        [int]$Indentation = 4,

        [Parameter(ParameterSetName = 'Prettify')]
        [switch]$AsArray
    )

    if ($PSCmdlet.ParameterSetName -eq 'Minify')
    {
        return ($Json | ConvertFrom-Json) | ConvertTo-Json -Depth 100 -Compress
    }

    # If the input JSON text has been created with ConvertTo-Json -Compress
    # then we first need to reconvert it without compression
    if ($Json -notmatch '\r?\n')
    {
        $Json = ($Json | ConvertFrom-Json) | ConvertTo-Json -Depth 100
    }

    $indent = 0
    $regexUnlessQuoted = '(?=([^"]*"[^"]*")*[^"]*$)'

    $result = $Json -split '\r?\n' |
    ForEach-Object {
        # If the line contains a ] or } character,
        # we need to decrement the indentation level unless it is inside quotes.
        if ($_ -match "[}\]]$regexUnlessQuoted")
        {
            $indent = [Math]::Max($indent - $Indentation, 0)
        }

        # Replace all colon-space combinations by ": " unless it is inside quotes.
        $line = (' ' * $indent) + ($_.TrimStart() -replace ":\s+$regexUnlessQuoted", ': ')

        # If the line contains a [ or { character,
        # we need to increment the indentation level unless it is inside quotes.
        if ($_ -match "[\{\[]$regexUnlessQuoted")
        {
            $indent += $Indentation
        }

        $line
    }

    if ($AsArray) { return $result }
    return $result -Join [Environment]::NewLine
}