In PowerShell, object-graphs are often used for applications along with modifying configurations resulted from e.g. Json or DSC (Desired State Configuration). Yet, most existing PowerShell cmdlets (as Sort-Object and Compare-Object) that manipulate objects treat object-graphs as flat object lists.
This toolkit contains an PowerShell object parser, an extended dot notation (Xdn) query selector and a set of Object Graph Cmdlets to deal with these complex recursive PowerShell objects.

Quote Wikipedia

In computer science, in an object-oriented program, groups of objects form a network through their relationships with each other, either through a direct reference to another object or through a chain of intermediate references. These groups of objects are referred to as object graphs, after the mathematical objects called graphs studied in graph theory.

Currently the tool set includes:

• Get-Node
• Get-ChildNode
• Test-ObjectGraph
• Compare-ObjectGraph
• Merge-ObjectGraph
• Sort-ObjectGraph
• Copy-ObjectGraph
• ConvertFrom-Expression
• ConvertTo-Expression
• Import-ObjectGraph
• Export-ObjectGraph

Install-Module -Name ObjectGraphTools