fix: use single quotes in new script files

.changeset/five-shoes-invent.md

@@ -0,0 +1,5 @@
+---
+'sv': patch
+---
+
+fix: improve formatting on new script files

packages/ast-tooling/index.ts

@@ -1,8 +1,8 @@
 import { parse as tsParse } from 'recast/parsers/typescript.js';
-import { parse as recastParse, print as recastPrint } from 'recast';
-import { Document, Element, Text, type ChildNode } from 'domhandler';
+import { parse as recastParse, print as recastPrint, type Options as RecastOptions } from 'recast';
+import { Document, Element, type ChildNode } from 'domhandler';
 import { ElementType, parseDocument } from 'htmlparser2';
-import { appendChild, prependChild, removeElement, textContent } from 'domutils';
+import { removeElement, textContent } from 'domutils';
 import serializeDom from 'dom-serializer';
 import {
 	Root as CssAst,
@@ -65,8 +65,17 @@ export function parseScript(content: string): AstTypes.Program {
 	return recastOutput.program;
 }
 
-export function serializeScript(ast: AstTypes.ASTNode): string {
-	return recastPrint(ast).code;
+export function serializeScript(ast: AstTypes.ASTNode, previousContent?: string): string {
+	let options: RecastOptions | undefined;
+	if (!previousContent) {
+		// provide sensible defaults if we generate a new file
+		options = {
+			quote: 'single',
+			useTabs: true
+		};
+	}
+
+	return recastPrint(ast, options).code;
 }
 
 export function parseCss(content: string): CssAst {
@@ -143,36 +152,6 @@ export function parseSvelte(content: string): SvelteAst {
 	return { jsAst, htmlAst, cssAst };
 }
 
-export function serializeSvelte(asts: SvelteAst): string {
-	const { jsAst, htmlAst, cssAst } = asts;
-
-	const css = serializeCss(cssAst);
-	const newScriptValue = serializeScript(jsAst);
-
-	if (newScriptValue.length > 0) {
-		const scriptTag = new Element('script', {}, undefined, ElementType.ElementType.Script);
-		for (const child of scriptTag.children) {
-			removeElement(child);
-		}
-
-		appendChild(scriptTag, new Text(newScriptValue));
-		prependChild(htmlAst, scriptTag);
-	}
-
-	if (css.length > 0) {
-		const styleTag = new Element('style', {}, undefined, ElementType.ElementType.Style);
-		for (const child of styleTag.children) {
-			removeElement(child);
-		}
-
-		appendChild(styleTag, new Text(css));
-		appendChild(htmlAst, styleTag);
-	}
-
-	const content = serializeHtml(htmlAst);
-	return content;
-}
-
 export function parseJson(content: string): any {
 	// some of the files we need to process contain comments. The default
 	// node JSON.parse fails parsing those comments.

packages/core/tests/js/arrays/object-array/output.ts

@@ -1,5 +1,5 @@
 const array = [{
   test: true
 }, {
-  test2: "string"
-}];
+  test2: 'string'
+}];

packages/core/tests/js/arrays/string-array/output.ts

@@ -1 +1 @@
-const array = ["test", "test2"];
+const array = ['test', 'test2'];

packages/core/tests/js/exports/default-export-with-variable/output.ts

@@ -1,5 +1,5 @@
 const object = {
-  test: "string"
+  test: 'string'
 };
 
 export default object;

packages/core/tests/js/exports/default-export/output.ts

@@ -1,3 +1,3 @@
 export default {
-  test: "string"
+  test: 'string'
 };

packages/core/tests/js/exports/named-export/output.ts

@@ -1,7 +1,7 @@
 export const variable = {
-  test: "string"
+  test: 'string'
 };
 
 export const variable2 = {
-  test2: "string2"
+  test2: 'string2'
 };

packages/core/tests/js/imports/default-import/output.ts

@@ -1 +1 @@
-import MyPackage from "package";
+import MyPackage from 'package';

packages/core/tests/js/imports/empty-import/output.ts

@@ -1,2 +1,2 @@
-import "package/file.css";
-import "./relativ/file.css";
+import 'package/file.css';
+import './relativ/file.css';

packages/core/tests/js/imports/named-import/output.ts

@@ -1,2 +1,2 @@
-import { Handle } from "@sveltejs/kit";
-import { namedOne } from "package";
+import { Handle } from '@sveltejs/kit';
+import { namedOne } from 'package';

packages/core/tests/js/index.ts

@@ -15,14 +15,14 @@ for (const categoryDirectory of categoryDirectories) {
 				const testDirectoryPath = join(baseDir, categoryDirectory, testName);
 
 				const inputFilePath = join(testDirectoryPath, 'input.ts');
-				const input = fs.existsSync(inputFilePath) ? fs.readFileSync(inputFilePath) : '';
-				const ast = parseScript(input.toString());
+				const input = fs.existsSync(inputFilePath) ? fs.readFileSync(inputFilePath, 'utf8') : '';
+				const ast = parseScript(input);
 
 				// dynamic imports always need to provide the path inline for static analysis
 				const module = await import(`./${categoryDirectory}/${testName}/run.ts`);
 				module.run({ ast });
 
-				const output = serializeScript(ast);
+				const output = serializeScript(ast, input);
 				await expect(output).toMatchFileSnapshot(`${testDirectoryPath}/output.ts`);
 			});
 		}

packages/core/tests/js/object/create/output.ts

@@ -2,5 +2,5 @@ const empty = {};
 
 const created = {
   foo: 1,
-  bar: "string"
+  bar: 'string'
 };

packages/core/tests/js/variables/declaration/output.ts

@@ -1,5 +1,5 @@
 const testNumber = 2;
 
 const testObject = {
-  foo: "bar"
+  foo: 'bar'
 };

packages/core/tooling/parsers.ts

@@ -8,7 +8,7 @@ type ParseBase = {
 
 export function parseScript(source: string): { ast: tools.AstTypes.Program } & ParseBase {
 	const ast = tools.parseScript(source);
-	const generateCode = () => tools.serializeScript(ast);
+	const generateCode = () => tools.serializeScript(ast, source);
 
 	return { ast, source, generateCode };
 }