"JSON with Comments" with the jsonc file extension is a natively supported file format in VS Code. JSONC adds JS-style comments to JSON files. ConvertFrom-Json currently does not support parsing JSONC strings. JSONC support could be added through either a -Comments switch or by default.

Background

Azure Resource Manager PowerShell and Azure Resource Manager templates are a critical component of the Azure ecosystem; many templates provided by Azure are large and complicated JSON files with over 1000 lines. Azure Resource Manager PowerShell cmdlets currently support JSONC templates, but cannot be used in conjunction with custom PowerShell validation due to the lack of JSONC support in ConvertFrom-Json