feat: remove transition import for ssr

src/compiler/compile/render_ssr/index.ts

@@ -145,6 +145,8 @@ export default function ssr(
 		main
 	].filter(Boolean);
 
+	remove_unused_import(component);
+
 	const js = b`
 		${css.code ? b`
 		const #css = {
@@ -185,3 +187,8 @@ function trim(nodes: TemplateNode[]) {
 
 	return nodes.slice(start, end);
 }
+
+const unused_import = new Set<any>(['svelte/transition']);
+function remove_unused_import(component: Component) {
+	component.imports = component.imports.filter(decl => !unused_import.has(decl.source.value));
+}

test/js/samples/ssr-remove-transition-import/_config.js

@@ -0,0 +1,6 @@
+export default {
+	options: {
+		generate: 'ssr',
+		preserveComments: true
+	}
+};

test/js/samples/ssr-remove-transition-import/expected.js

@@ -0,0 +1,10 @@
+/* generated by Svelte vX.Y.Z */
+import { create_ssr_component, escape } from "svelte/internal";
+
+let name = "world";
+
+const Component = create_ssr_component(($$result, $$props, $$bindings, $$slots) => {
+	return `<h1>Hello ${escape(name)}!</h1>`;
+});
+
+export default Component;

test/js/samples/ssr-remove-transition-import/input.svelte

@@ -0,0 +1,6 @@
+<script>
+	import { fly } from 'svelte/transition';
+	let name = 'world';
+</script>
+
+<h1 transition:fly={{duration: 150, y: 50}}>Hello {name}!</h1>