feat(tsx): Return interesting ranges for TSX output

.changeset/fair-windows-wave.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/compiler': minor
+---
+
+Return generated frontmatter and body ranges in TSX output

cmd/astro-wasm/astro-wasm.go

@@ -173,6 +173,7 @@ type TSXResult struct {
 	Code        string                  `js:"code"`
 	Map         string                  `js:"map"`
 	Diagnostics []loc.DiagnosticMessage `js:"diagnostics"`
+	Ranges      printer.TSXRanges       `js:"metaRanges"`
 }
 
 type TransformResult struct {
@@ -269,6 +270,7 @@ func ConvertToTSX() any {
 			Code:        code,
 			Map:         sourcemapString,
 			Diagnostics: h.Diagnostics(),
+			Ranges:      result.TSXRanges,
 		}).Value
 	})
 }

internal/loc/loc.go

@@ -20,6 +20,11 @@ type Span struct {
 	Start, End int
 }
 
+type TSXRange struct {
+	Start int `js:"start"`
+	End   int `js:"end"`
+}
+
 // A NodeType is the type of a Node.
 type DiagnosticSeverity int
 

internal/printer/print-to-tsx.go

@@ -31,9 +31,15 @@ func PrintToTSX(sourcetext string, n *Node, opts transform.TransformOptions, h *
 	return PrintResult{
 		Output:         p.output,
 		SourceMapChunk: p.builder.GenerateChunk(p.output),
+		TSXRanges:      p.ranges,
 	}
 }
 
+type TSXRanges struct {
+	Frontmatter loc.TSXRange `js:"frontmatter"`
+	Body        loc.TSXRange `js:"body"`
+}
+
 func isScript(p *astro.Node) bool {
 	return p.DataAtom == atom.Script
 }
@@ -106,6 +112,7 @@ func renderTsx(p *printer, n *Node) {
 		props := js_scanner.GetPropsType(source)
 		hasGetStaticPaths := js_scanner.HasGetStaticPaths(source)
 		hasChildren := false
+		startLoc := len(p.output)
 		for c := n.FirstChild; c != nil; c = c.NextSibling {
 			// This checks for the first node that comes *after* the frontmatter
 			// to ensure that the statement is properly closed with a `;`.
@@ -123,11 +130,18 @@ func renderTsx(p *printer, n *Node) {
 				// We always need to start the body with `<Fragment>`
 				p.addNilSourceMapping()
 				p.print("<Fragment>\n")
+
+				// Update the start location of the body to the start of the first child
+				startLoc = len(p.output)
+
 				hasChildren = true
 			}
 			if c.PrevSibling == nil && c.Type != FrontmatterNode {
 				p.addNilSourceMapping()
 				p.print("<Fragment>\n")
+
+				startLoc = len(p.output)
+
 				hasChildren = true
 			}
 			renderTsx(p, c)
@@ -136,6 +150,11 @@ func renderTsx(p *printer, n *Node) {
 		p.print("\n")
 
 		p.addNilSourceMapping()
+		p.setTSXBodyRange(loc.TSXRange{
+			Start: startLoc,
+			End:   len(p.output),
+		})
+
 		// Only close the body with `</Fragment>` if we printed a body
 		if hasChildren {
 			p.print("</Fragment>\n")
@@ -176,6 +195,7 @@ declare const Astro: Readonly<import('astro').AstroGlobal<%s, typeof %s`, propsI
 
 	if n.Type == FrontmatterNode {
 		p.addSourceMapping(loc.Loc{Start: 0})
+		frontmatterStart := len(p.output)
 		for c := n.FirstChild; c != nil; c = c.NextSibling {
 			if c.Type == TextNode {
 				if len(c.Loc) > 0 {
@@ -192,6 +212,10 @@ declare const Astro: Readonly<import('astro').AstroGlobal<%s, typeof %s`, propsI
 			p.addSourceMapping(loc.Loc{Start: n.FirstChild.Loc[0].Start + len(n.FirstChild.Data) + 3})
 			p.println("")
 		}
+		p.setTSXFrontmatterRange(loc.TSXRange{
+			Start: frontmatterStart,
+			End:   len(p.output),
+		})
 		return
 	}
 

internal/printer/printer.go

@@ -19,6 +19,8 @@ import (
 type PrintResult struct {
 	Output         []byte
 	SourceMapChunk sourcemap.Chunk
+	// Optional, used only for TSX output
+	TSXRanges TSXRanges
 }
 
 type printer struct {
@@ -31,6 +33,9 @@ type printer struct {
 	hasInternalImports bool
 	hasCSSImports      bool
 	needsTransitionCSS bool
+
+	// Optional, used only for TSX output
+	ranges TSXRanges
 }
 
 var TEMPLATE_TAG = "$$render"
@@ -68,6 +73,14 @@ func (p *printer) println(text string) {
 	p.print(text + "\n")
 }
 
+func (p *printer) setTSXFrontmatterRange(frontmatterRange loc.TSXRange) {
+	p.ranges.Frontmatter = frontmatterRange
+}
+
+func (p *printer) setTSXBodyRange(componentRange loc.TSXRange) {
+	p.ranges.Body = componentRange
+}
+
 func (p *printer) printTextWithSourcemap(text string, l loc.Loc) {
 	start := l.Start
 	for pos, c := range text {

packages/compiler/src/shared/types.ts

@@ -106,6 +106,16 @@ export interface TSXResult {
   code: string;
   map: SourceMap;
   diagnostics: DiagnosticMessage[];
+  metaRanges: {
+    frontmatter: {
+      start: number;
+      end: number;
+    };
+    body: {
+      start: number;
+      end: number;
+    };
+  };
 }
 
 export interface ParseResult {

packages/compiler/test/tsx/basic.ts

@@ -245,4 +245,36 @@ export default function __AstroComponent_(_props: Record<string, any>): any {}\n
   assert.snapshot(code, output, `expected code to match snapshot`);
 });
 
+test('return ranges', async () => {
+  const input = `---\nconsole.log("Hello!")\n---\n\n<div></div>`;
+  const { metaRanges } = await convertToTSX(input, { sourcemap: 'external' });
+
+  assert.equal(metaRanges, {
+    frontmatter: {
+      start: 31,
+      end: 55,
+    },
+    body: {
+      start: 69,
+      end: 81,
+    },
+  });
+});
+
+test('return ranges - no frontmatter', async () => {
+  const input = `<div></div>`;
+  const { metaRanges } = await convertToTSX(input, { sourcemap: 'external' });
+
+  assert.equal(metaRanges, {
+    frontmatter: {
+      start: 31,
+      end: 31,
+    },
+    body: {
+      start: 42,
+      end: 54,
+    },
+  });
+});
+
 test.run();

packages/compiler/test/tsx/escape.ts

@@ -1,10 +1,11 @@
 import { convertToTSX } from '@astrojs/compiler';
 import { test } from 'uvu';
 import * as assert from 'uvu/assert';
+import { TSXPrefix } from '../utils';
 
 test('escapes braces in comment', async () => {
   const input = `<!-- {<div>Not JSX!<div/>}-->`;
-  const output = `<Fragment>
+  const output = `${TSXPrefix}<Fragment>
 {/** \\\\{<div>Not JSX!<div/>\\\\}*/}
 </Fragment>
 export default function __AstroComponent_(_props: Record<string, any>): any {}\n`;
@@ -14,7 +15,7 @@ export default function __AstroComponent_(_props: Record<string, any>): any {}\n
 
 test('always inserts space before comment', async () => {
   const input = `<!--/<div>Error?<div/>-->`;
-  const output = `<Fragment>
+  const output = `${TSXPrefix}<Fragment>
 {/** /<div>Error?<div/>*/}
 </Fragment>
 export default function __AstroComponent_(_props: Record<string, any>): any {}\n`;
@@ -24,7 +25,7 @@ export default function __AstroComponent_(_props: Record<string, any>): any {}\n
 
 test('simple escapes star slashes (*/)', async () => {
   const input = `<!--*/<div>Evil comment<div/>-->`;
-  const output = `<Fragment>
+  const output = `${TSXPrefix}<Fragment>
 {/** *\\/<div>Evil comment<div/>*/}
 </Fragment>
 export default function __AstroComponent_(_props: Record<string, any>): any {}\n`;
@@ -34,7 +35,7 @@ export default function __AstroComponent_(_props: Record<string, any>): any {}\n
 
 test('multiple escapes star slashes (*/)', async () => {
   const input = `<!--***/*/**/*/*/*/<div>Even more evil comment<div/>-->`;
-  const output = `<Fragment>
+  const output = `${TSXPrefix}<Fragment>
 {/** ***\\/*\\/**\\/*\\/*\\/*\\/<div>Even more evil comment<div/>*/}
 </Fragment>
 export default function __AstroComponent_(_props: Record<string, any>): any {}\n`;