How can I format documents that are not saved in visual studio code?

Question

If i Shift + Alt + F (or use the command from the palette) on a Untitled tab on vscode the following command appear:

There is no formatter for 'plaintext' files installed.

Is there any way to specify a different format for the unsaved file to enable the formatter of choice?

This need usually arise when I usually copy/paste some json/xml.

Answer 1

I found two solutions to this specific problem, even if they seems more a workaround than a proper solution:

1. Using a specific extension to format particular code (json or xml)
2. Trick VSCode into thinking default unsaved files are json

1 Extensions that format as specific code

Install specific extension that add language specific commands:

• XML Tools
  default keybinding Ctrl + Shift + Alt + B
• JSON Tools
  default keybinding Ctrl + Alt + M

PRO

• no default settings are changed
• specific format can be used on any selection in any file
• it's the same solution that notepad++ implement

CONS

• additional extensions to download may look overkill only to format something
• more keybindings and additional non standard behaviours

2 VSCode default unsaved files trick

Add a configuration to settings.json that specify json as the type of document for untitled files:

"files.associations": {
    "Untitled-*" : "json"
}

PRO

• default Format document is used
• no additional download is required

CONS

• only one format can be specified
• locale-dependant (in languages other than English it should not work)