add printCode(ast)

package.json

@@ -1,5 +1,5 @@
 {
-    "name": "prettier-plugin-svelte",
+    "name": "@mizchi/svelte-printer",
     "version": "2.1.6",
     "description": "Svelte plugin for prettier",
     "main": "plugin.js",
@@ -28,13 +28,13 @@
     },
     "homepage": "https://github.com/sveltejs/prettier-plugin-svelte#readme",
     "devDependencies": {
+        "@rollup/plugin-commonjs": "14.0.0",
+        "@rollup/plugin-node-resolve": "11.0.1",
         "@types/node": "^10.12.18",
         "@types/prettier": "^2.1.6",
         "ava": "3.15.0",
         "prettier": "^2.2.1",
         "rollup": "2.36.0",
-        "@rollup/plugin-commonjs": "14.0.0",
-        "@rollup/plugin-node-resolve": "11.0.1",
         "rollup-plugin-typescript": "1.0.1",
         "svelte": "^3.30.0",
         "ts-node": "^9.1.1",
@@ -44,5 +44,8 @@
     "peerDependencies": {
         "prettier": "^1.16.4 || ^2.0.0",
         "svelte": "^3.2.0"
+    },
+    "dependencies": {
+        "astring": "^1.7.0"
     }
 }

src/index.ts

@@ -65,3 +65,5 @@ export const printers: Record<string, Printer> = {
 };
 
 export { options } from './options';
+
+export { printCode } from './printCode';

src/print/index.ts

@@ -6,6 +6,7 @@ import { hasSnippedContent, unsnipContent } from '../lib/snipTagContent';
 import { parseSortOrder, SortOrderPart } from '../options';
 import { isEmptyDoc, isLine, trim, trimRight } from './doc-helpers';
 import { flatten, isASTNode, isPreTagContent } from './helpers';
+import { generate } from 'astring';
 import {
     checkWhitespaceAtEndOfSvelteBlock,
     checkWhitespaceAtStartOfSvelteBlock,
@@ -622,8 +623,12 @@ export function print(path: FastPath, options: ParserOptions, print: PrintFn): D
             return concat([line, '{...', printJS(path, print, false, false, 'expression'), '}']);
     }
 
-    console.error(JSON.stringify(node, null, 4));
-    throw new Error('unknown node type: ' + node.type);
+    try {
+        return generate(node);
+    } catch (err) {
+        console.error(JSON.stringify(node, null, 4));
+        throw new Error('unknown node type: ' + node.type);
+    }
 }
 
 function printTopLevelParts(

src/printCode.ts

@@ -0,0 +1,22 @@
+import type { Ast } from 'svelte/types/compiler/interfaces';
+import prettier from 'prettier/standalone';
+import * as p from './index';
+
+export function printCode(ast: Ast) {
+    const overridePlugin = {
+        ...p,
+        parsers: {
+            ...p.parsers,
+            svelte: {
+                ...p.parsers.svelte,
+                parse: () => {
+                    return { ...ast, __isRoot: true };
+                },
+            },
+        },
+    };
+    return prettier.format(' dummy ', {
+        parser: 'svelte',
+        plugins: [overridePlugin as any],
+    });
+}