fix: Source maps and having sequence built-in (#48)

.changeset/plenty-chicken-sparkle.md

@@ -0,0 +1,5 @@
+---
+'@melt-ui/pp': patch
+---
+
+fix: Fixed source maps

.changeset/rude-games-think.md

@@ -0,0 +1,5 @@
+---
+'@melt-ui/pp': minor
+---
+
+feat: Added a built-in sequential preprocessor

src/index.ts

@@ -6,6 +6,8 @@ import { traverse } from './traverse/index.js';
 import type { TemplateNode } from 'svelte/types/compiler/interfaces';
 import type { Config, Node } from './types.js';
 
+export * from './sequence.js';
+
 export type PreprocessOptions = {
 	/**
 	 * For aliasing the name of the `melt` action.
@@ -119,7 +121,6 @@ export function preprocessMeltUI(options?: PreprocessOptions): PreprocessorGroup
 
 			return {
 				code: config.markup.toString(),
-				map: config.markup.generateMap(),
 			};
 		},
 	};

src/sequence.ts

@@ -0,0 +1,53 @@
+// Originally sourced and modified from https://github.com/pchynoweth/svelte-sequential-preprocessor
+
+import { preprocess } from 'svelte/compiler';
+import { PreprocessorGroup, Processed } from 'svelte/types/compiler/preprocess';
+
+/**
+ * A Svelte preprocessor that wraps other preprocessors and forces them to run sequentially.
+ *
+ * @example
+ * ```js
+ * // svelte.config.js
+ * import { preprocessMeltUI, sequence } from '@melt-ui/pp';
+ *
+ * const config = {
+ * 	// ... other svelte config options
+ * 	preprocess: sequence([
+ * 		// ... other preprocessors (e.g. `vitePreprocess()`)
+ * 		preprocessMeltUI()
+ * 	])
+ * 	// ...
+ * };
+ * ```
+ */
+export function sequence(preprocessors: PreprocessorGroup[]): PreprocessorGroup {
+	return {
+		async markup({ content, filename }): Promise<Processed> {
+			let code = content;
+			let map: Processed['map'];
+			let attributes: Processed['attributes'];
+			let toString: Processed['toString'];
+			const dependencies: Processed['dependencies'] = [];
+
+			for (const pp of preprocessors) {
+				const processed = await preprocess(code, pp, { filename });
+				if (processed && processed.dependencies) {
+					dependencies.push(...processed.dependencies);
+				}
+				code = processed ? processed.code : code;
+				map = processed.map ?? map;
+				attributes = processed.attributes ?? attributes;
+				toString = processed.toString ?? toString;
+			}
+
+			return {
+				code,
+				dependencies,
+				map,
+				attributes,
+				toString,
+			};
+		},
+	};
+}