revert: top level returns transformations (#1036)

.changeset/brown-terms-sleep.md

@@ -0,0 +1,5 @@
+---
+"@astrojs/compiler": patch
+---
+
+Revert the transformation of top-level returns into throws in TSX as it was buggy in numerous situations

internal/js_scanner/js_scanner.go

@@ -12,60 +12,6 @@ import (
 	"github.com/withastro/compiler/internal/loc"
 )
 
-func FindTopLevelReturns(source []byte) []int {
-	l := js.NewLexer(parse.NewInputBytes(source))
-	i := 0
-	returns := make([]int, 0)
-	pairs := make(map[byte]int)
-	inFunction := false
-
-	for {
-		token, value := l.Next()
-
-		if token == js.DivToken || token == js.DivEqToken {
-			lns := bytes.Split(source[i+1:], []byte{'\n'})
-			if bytes.Contains(lns[0], []byte{'/'}) {
-				token, value = l.RegExp()
-			}
-		}
-
-		if token == js.ErrorToken {
-			if l.Err() != io.EOF {
-				return returns
-			}
-			break
-		}
-
-		if js.IsPunctuator(token) {
-			if value[0] == '{' {
-				pairs[value[0]]++
-				i += len(value)
-				continue
-			} else if value[0] == '}' {
-				pairs['{']--
-			}
-		}
-
-		// Track function declarations
-		if token == js.FunctionToken {
-			inFunction = true
-		}
-
-		// Track end of function declarations
-		if inFunction && token == js.CloseBraceToken && pairs['{'] == 1 {
-			inFunction = false
-		}
-
-		if token == js.ReturnToken && !inFunction {
-			returns = append(returns, i)
-		}
-
-		i += len(value)
-	}
-
-	return returns
-}
-
 type HoistedScripts struct {
 	Hoisted     [][]byte
 	HoistedLocs []loc.Loc

internal/printer/print-to-tsx.go

@@ -2,7 +2,6 @@ package printer
 
 import (
 	"fmt"
-	"slices"
 	"strings"
 	"unicode"
 
@@ -404,31 +403,11 @@ declare const Astro: Readonly<import('astro').AstroGlobal<%s, typeof %s`, propsI
 		p.addSourceMapping(loc.Loc{Start: 0})
 		frontmatterStart := len(p.output)
 		for c := n.FirstChild; c != nil; c = c.NextSibling {
-			topLevelReturn := js_scanner.FindTopLevelReturns([]byte(c.Data))
 			if c.Type == TextNode {
 				if len(c.Loc) > 0 {
 					p.addSourceMapping(c.Loc[0])
 				}
-				// Remplace all the top level returns with a `throw`
-				if len(topLevelReturn) > 0 {
-					// Loop over the characters and replace the top level returns with a `throw`
-					newString := []byte{}
-
-					i := 0
-					for i < len(c.Data) {
-						if slices.Contains(topLevelReturn, i) {
-							newString = append(newString, []byte("throw ")...)
-							i += len("return")
-						} else {
-							newString = append(newString, c.Data[i])
-							i++
-						}
-					}
-
-					p.printTextWithSourcemap(string(newString), c.Loc[0])
-				} else {
-					p.printTextWithSourcemap(c.Data, c.Loc[0])
-				}
+				p.printTextWithSourcemap(c.Data, c.Loc[0])
 			} else {
 				renderTsx(p, c, o)
 			}