Function print

print(node, options?): string

Print AST SvelteAST.BaseNode as a string. Aka parse in reverse.

How does it work under the hood?

Firstly, it determines whether the provided AST node is unique node for Svelte SvelteAST.Node.
Based on type check guard from above:
- it uses either this package's Printer to print Svelte AST node,
- otherwise it uses esrap print_es to print ESTree specification-complaint AST node

How to use it?

Parameters

node: Node
Svelte or ESTree AST node
options: Partial<PrintOptions> = {}
printing options

Returns string

Stringified Svelte AST node TODO: Ask Svelte maintainers if Script and SvelteOptions were omittted from SvelteNode intentionally - possibly forgotten to include

Example: writing a codemode using Node.js

  import fs from "node:fs";

  import { print } from "svelte-ast-print";
  import { parse } from "svelte/compiler";

  const originalSvelteCode = fs.readFileSync("src/App.svelte", "utf-8");
  let svelteAST = parse(originalSvelteCode, { modern: true });
  //                                          👆 For now, only modern is supported.
  //                                             By default is 'false'.
  //                                             Is it planned to be 'true' from Svelte v6+

  // ...
  // Do some modifications on this AST...
  // e.g. transform `<slot />` to `{@render children()}`
  // ...

  const output = print(svelteAST); // AST is now a stringified code output! 🎉

  fs.writeFileSync("src/App.svelte", output, { encoding: " utf-8" });