Skip printing createAstro code if unused

.changeset/khaki-ways-wait.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/compiler': patch
+---
+
+Skips printing `createAstro` code if the `Astro` global is not referenced

internal/printer/print-to-js.go

@@ -148,6 +148,9 @@ func render1(p *printer, n *Node, opts RenderOptions) {
 		return
 	}
 
+	// Decide whether to print code for `Astro` global variable. Use a loose check for now.
+	printAstroGlobal := strings.Contains(p.sourcetext, "Astro")
+
 	// Render frontmatter (will be the first node, if it exists)
 	if n.Type == FrontmatterNode {
 		if n.FirstChild == nil {
@@ -179,9 +182,11 @@ func render1(p *printer, n *Node, opts RenderOptions) {
 				// 1. Component imports, if any exist.
 				p.addNilSourceMapping()
 				p.printComponentMetadata(n.Parent, opts.opts, []byte(p.sourcetext))
-				// 2. Top-level Astro global.
 
-				p.printTopLevelAstro(opts.opts)
+				// 2. Top-level Astro global.
+				if printAstroGlobal {
+					p.printTopLevelAstro(opts.opts)
+				}
 
 				exports := make([][]byte, 0)
 				exportLocs := make([]loc.Loc, 0)
@@ -228,7 +233,7 @@ func render1(p *printer, n *Node, opts RenderOptions) {
 					}
 				}
 
-				p.printFuncPrelude(opts.opts)
+				p.printFuncPrelude(opts.opts, printAstroGlobal)
 				// PRINT BODY
 				if len(bodies) > 0 {
 					for i, body := range bodies {
@@ -267,10 +272,12 @@ func render1(p *printer, n *Node, opts RenderOptions) {
 		return
 	} else if !p.hasFuncPrelude {
 		p.printComponentMetadata(n.Parent, opts.opts, []byte{})
-		p.printTopLevelAstro(opts.opts)
+		if printAstroGlobal {
+			p.printTopLevelAstro(opts.opts)
+		}
 
 		// Render func prelude. Will only run for the first non-frontmatter node
-		p.printFuncPrelude(opts.opts)
+		p.printFuncPrelude(opts.opts, printAstroGlobal)
 		// This just ensures a newline
 		p.println("")
 

internal/printer/printer.go

@@ -264,17 +264,19 @@ func (p *printer) printDefineVarsClose(n *astro.Node) {
 	}
 }
 
-func (p *printer) printFuncPrelude(opts transform.TransformOptions) {
+func (p *printer) printFuncPrelude(opts transform.TransformOptions, printAstroGlobal bool) {
 	if p.hasFuncPrelude {
 		return
 	}
 	componentName := getComponentName(opts.Filename)
 	p.addNilSourceMapping()
 	p.println(fmt.Sprintf("const %s = %s(async (%s, $$props, %s) => {", componentName, CREATE_COMPONENT, RESULT, SLOTS))
-	p.addNilSourceMapping()
-	p.println(fmt.Sprintf("const Astro = %s.createAstro($$Astro, $$props, %s);", RESULT, SLOTS))
-	p.addNilSourceMapping()
-	p.println(fmt.Sprintf("Astro.self = %s;", componentName))
+	if printAstroGlobal {
+		p.addNilSourceMapping()
+		p.println(fmt.Sprintf("const Astro = %s.createAstro($$Astro, $$props, %s);", RESULT, SLOTS))
+		p.addNilSourceMapping()
+		p.println(fmt.Sprintf("Astro.self = %s;", componentName))
+	}
 	p.hasFuncPrelude = true
 }
 

internal/printer/printer_test.go

@@ -35,9 +35,9 @@ var INTERNAL_IMPORTS = fmt.Sprintf("import {\n  %s\n} from \"%s\";\n", strings.J
 	"renderScript as " + RENDER_SCRIPT,
 	"createMetadata as " + CREATE_METADATA,
 }, ",\n  "), "http://localhost:3000/")
-var PRELUDE = fmt.Sprintf(`const $$Component = %s(async ($$result, $$props, %s) => {
-const Astro = $$result.createAstro($$Astro, $$props, %s);
-Astro.self = $$Component;%s`, CREATE_COMPONENT, SLOTS, SLOTS, "\n\n")
+var PRELUDE = fmt.Sprintf(`const $$Component = %s(async ($$result, $$props, %s) => {`, CREATE_COMPONENT, SLOTS)
+var PRELUDE_ASTRO_GLOBAL = fmt.Sprintf(`const Astro = $$result.createAstro($$Astro, $$props, %s);
+Astro.self = $$Component;`, SLOTS)
 var RETURN = fmt.Sprintf("return %s%s", TEMPLATE_TAG, BACKTICK)
 var SUFFIX = fmt.Sprintf("%s;", BACKTICK) + `
 }, undefined, undefined);
@@ -3571,6 +3571,8 @@ const meta = { title: 'My App' };
 			}, h)
 			output := string(result.Output)
 
+			// The compiler prints Astro global code only if it's loosely used
+			printAstroGlobal := strings.Contains(tt.source, "Astro")
 			toMatch := INTERNAL_IMPORTS
 			if strings.Count(tt.source, "transition:") > 0 {
 				toMatch += `import "transitions.css";`
@@ -3654,11 +3656,17 @@ const meta = { title: 'My App' };
 				patharg = fmt.Sprintf("\"%s\"", escapedFilename)
 			}
 			toMatch += "\n\n" + fmt.Sprintf("export const %s = %s(%s, %s);\n\n", METADATA, CREATE_METADATA, patharg, metadata)
-			toMatch += test_utils.Dedent(CREATE_ASTRO_CALL) + "\n"
+			if printAstroGlobal {
+				toMatch += test_utils.Dedent(CREATE_ASTRO_CALL) + "\n"
+			}
 			if len(tt.want.getStaticPaths) > 0 {
 				toMatch += strings.TrimSpace(test_utils.Dedent(tt.want.getStaticPaths)) + "\n\n"
 			}
-			toMatch += test_utils.Dedent(PRELUDE) + "\n"
+			if printAstroGlobal {
+				toMatch += test_utils.Dedent(PRELUDE) + test_utils.Dedent(PRELUDE_ASTRO_GLOBAL) + "\n"
+			} else {
+				toMatch += test_utils.Dedent(PRELUDE) + "\n"
+			}
 			if len(tt.want.frontmatter) > 1 {
 				toMatch += strings.TrimSpace(test_utils.Dedent(tt.want.frontmatter[1]))
 			}