Query: Can prettier create a js file from an AST

[jaitaiwan]

Hi, I've gone through and tried to find similar issues one of which is #1059.

I'm looking at creating some sort of visual scripting interface for JavaScript as a personal project. I'm very much on board with Prettier's goal, so I feel that code generated by the Visual Scripting tool should result in the same code as prettier would output. So I have a similar question to what the person in 1059 has:

Is there an exposed api that would allow me to input a programatically created AST into prettier and output a Javascript file?

[bakkot]

#2068 would presumably provide this, but to my knowledge there's nothing currently. Your best bet at the moment is probably using something like @babel/generator or escodegen or shift-codegen to turn your AST into an unformatted string, then pass that to Prettier. It adds a bit of overhead (though less than you might expect), but it works.

[thorn0]

It's possible to do this using the Custom Parser API:

// suppose you have your AST in the yourAst variable
const formatted = prettier.format(
  ".", // any non-empty, non-whitespace string 
  { parser: () => yourAst }
);

But keep in mind that Prettier mutates the AST.

[benatkin]

Worth reading about gofmt's substitution command https://golang.org/cmd/gofmt/

[thorn0]

Closing in favor of #9114