diff --git a/.gitignore b/.gitignore
index 930c8dc863..dbed468f15 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,10 +3,10 @@
 node_modules
 *.map
 /cli/
-/compiler/
-/ssr/
-/internal.js
 /compiler.js
+/index.js
+/internal.*
+/store.js
 /scratch/
 /coverage/
 /coverage.lcov/
@@ -15,7 +15,6 @@ node_modules
 /test/sourcemaps/samples/*/output.js.map
 /test/sourcemaps/samples/*/output.css
 /test/sourcemaps/samples/*/output.css.map
-/store.umd.js
 /yarn-error.log
 _actual*.*
-_*/
\ No newline at end of file
+_*/
diff --git a/index.js b/index.mjs
similarity index 77%
rename from index.js
rename to index.mjs
index 9fdeadb8fa..44031c35c8 100644
--- a/index.js
+++ b/index.mjs
@@ -4,4 +4,4 @@ export {
 	beforeUpdate,
 	afterUpdate,
 	createEventDispatcher
-} from './internal.js';
+} from './internal';
diff --git a/package.json b/package.json
index 4844644834..f12c429aa9 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,7 @@
   "name": "svelte",
   "version": "3.0.0-alpha6",
   "description": "The magical disappearing UI framework",
+  "module": "index.mjs",
   "main": "index.js",
   "bin": {
     "svelte": "svelte"
@@ -10,9 +11,9 @@
     "cli",
     "compiler.js",
     "register.js",
-    "index.js",
-    "internal.js",
-    "store.js",
+    "index.*",
+    "internal.*",
+    "store.*",
     "svelte",
     "README.md"
   ],
diff --git a/rollup.config.js b/rollup.config.js
index 3229a2800f..1bb01c9282 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -1,14 +1,12 @@
-import path from 'path';
 import replace from 'rollup-plugin-replace';
 import resolve from 'rollup-plugin-node-resolve';
 import commonjs from 'rollup-plugin-commonjs';
 import json from 'rollup-plugin-json';
 import typescript from 'rollup-plugin-typescript';
-import buble from 'rollup-plugin-buble';
 import pkg from './package.json';
 
 export default [
-	/* compiler/svelte.js */
+	/* compiler.js */
 	{
 		input: 'src/index.ts',
 		plugins: [
@@ -54,12 +52,38 @@ export default [
 		experimentalCodeSplitting: true
 	},
 
-	/* internal.js */
+	/* index.js */
+	{
+		input: 'index.mjs',
+		output: {
+			file: 'index.js',
+			format: 'cjs'
+		},
+		external: name => name !== 'index.mjs'
+	},
+
+	/* internal.[m]js */
 	{
 		input: 'src/internal/index.js',
+		output: [
+			{
+				file: 'internal.mjs',
+				format: 'esm'
+			},
+			{
+				file: 'internal.js',
+				format: 'cjs'
+			}
+		]
+	},
+
+	/* store.js */
+	{
+		input: 'store.mjs',
 		output: {
-			file: 'internal.js',
-			format: 'es'
-		}
-	}
+			file: 'store.js',
+			format: 'cjs'
+		},
+		external: name => name !== 'store.mjs'
+	},
 ];
diff --git a/src/compile/wrapModule.ts b/src/compile/wrapModule.ts
index 003c4d6815..76dbe020bc 100644
--- a/src/compile/wrapModule.ts
+++ b/src/compile/wrapModule.ts
@@ -27,7 +27,7 @@ export default function wrapModule(
 	module_exports: Export[],
 	source: string
 ): string {
-	const internalPath = `${sveltePath}/internal.js`;
+	const internalPath = `${sveltePath}/internal`;
 
 	if (format === 'esm') {
 		return esm(code, name, options, banner, sveltePath, internalPath, helpers, imports, module_exports, source);
diff --git a/store.js b/store.mjs
similarity index 97%
rename from store.js
rename to store.mjs
index d22afdedee..ffdd90bf0e 100644
--- a/store.js
+++ b/store.mjs
@@ -1,4 +1,4 @@
-import { run_all, noop } from './internal.js';
+import { run_all, noop } from './internal';
 
 export function readable(start, value) {
 	const subscribers = [];
diff --git a/test/custom-elements/index.js b/test/custom-elements/index.js
index 1c4e64cf28..ad9e6004dc 100644
--- a/test/custom-elements/index.js
+++ b/test/custom-elements/index.js
@@ -51,8 +51,8 @@ describe('custom-elements', function() {
 
 		const solo = /\.solo$/.test(dir);
 		const skip = /\.skip$/.test(dir);
-		const internal = path.resolve('internal.js');
-		const index = path.resolve('index.js');
+		const internal = path.resolve('internal.mjs');
+		const index = path.resolve('index.mjs');
 
 		(solo ? it.only : skip ? it.skip : it)(dir, () => {
 			const config = loadConfig(`./custom-elements/samples/${dir}/_config.js`);
@@ -62,7 +62,7 @@ describe('custom-elements', function() {
 				plugins: [
 					{
 						resolveId(importee) {
-							if (importee === 'svelte/internal.js') {
+							if (importee === 'svelte/internal') {
 								return internal;
 							}
 
@@ -118,4 +118,4 @@ describe('custom-elements', function() {
 
 		});
 	});
-});
\ No newline at end of file
+});
diff --git a/test/js/samples/action-custom-event-handler/expected.js b/test/js/samples/action-custom-event-handler/expected.js
index 3451ef6dc5..8b0241ed47 100644
--- a/test/js/samples/action-custom-event-handler/expected.js
+++ b/test/js/samples/action-custom-event-handler/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createElement, detachNode, flush, init, insert, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createElement, detachNode, flush, init, insert, noop, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var button, foo_action, current;
diff --git a/test/js/samples/action/expected.js b/test/js/samples/action/expected.js
index b3e8fe20d5..97f776295a 100644
--- a/test/js/samples/action/expected.js
+++ b/test/js/samples/action/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createElement, detachNode, init, insert, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createElement, detachNode, init, insert, noop, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var a, link_action, current;
diff --git a/test/js/samples/bind-width-height/expected.js b/test/js/samples/bind-width-height/expected.js
index 42c4d087b2..65c9bf9f14 100644
--- a/test/js/samples/bind-width-height/expected.js
+++ b/test/js/samples/bind-width-height/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, addResizeListener, add_render_callback, createElement, detachNode, flush, init, insert, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, addResizeListener, add_render_callback, createElement, detachNode, flush, init, insert, noop, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var div, div_resize_listener, current;
diff --git a/test/js/samples/collapses-text-around-comments/expected.js b/test/js/samples/collapses-text-around-comments/expected.js
index df67257c96..4d13bfe165 100644
--- a/test/js/samples/collapses-text-around-comments/expected.js
+++ b/test/js/samples/collapses-text-around-comments/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 function add_css() {
 	var style = createElement("style");
diff --git a/test/js/samples/component-static-array/expected.js b/test/js/samples/component-static-array/expected.js
index dc8ea83544..abbde3284c 100644
--- a/test/js/samples/component-static-array/expected.js
+++ b/test/js/samples/component-static-array/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, init, mount_component, noop, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, init, mount_component, noop, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var current;
diff --git a/test/js/samples/component-static-immutable/expected.js b/test/js/samples/component-static-immutable/expected.js
index 357d7c20ea..71cb810a5d 100644
--- a/test/js/samples/component-static-immutable/expected.js
+++ b/test/js/samples/component-static-immutable/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, init, mount_component, noop, not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, init, mount_component, noop, not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var current;
diff --git a/test/js/samples/component-static-immutable2/expected.js b/test/js/samples/component-static-immutable2/expected.js
index 357d7c20ea..71cb810a5d 100644
--- a/test/js/samples/component-static-immutable2/expected.js
+++ b/test/js/samples/component-static-immutable2/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, init, mount_component, noop, not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, init, mount_component, noop, not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var current;
diff --git a/test/js/samples/component-static/expected.js b/test/js/samples/component-static/expected.js
index 4201f86c21..6f53c66d88 100644
--- a/test/js/samples/component-static/expected.js
+++ b/test/js/samples/component-static/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, init, mount_component, noop, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, init, mount_component, noop, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var current;
diff --git a/test/js/samples/computed-collapsed-if/expected.js b/test/js/samples/computed-collapsed-if/expected.js
index 3e5ed4f081..14b0dfe978 100644
--- a/test/js/samples/computed-collapsed-if/expected.js
+++ b/test/js/samples/computed-collapsed-if/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, flush, init, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, flush, init, noop, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var current;
diff --git a/test/js/samples/css-media-query/expected.js b/test/js/samples/css-media-query/expected.js
index 330aa036c7..4a9c0e2c4a 100644
--- a/test/js/samples/css-media-query/expected.js
+++ b/test/js/samples/css-media-query/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, createElement, detachNode, init, insert, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, createElement, detachNode, init, insert, noop, run, safe_not_equal } from "svelte/internal";
 
 function add_css() {
 	var style = createElement("style");
diff --git a/test/js/samples/css-shadow-dom-keyframes/expected.js b/test/js/samples/css-shadow-dom-keyframes/expected.js
index a5b82a4fad..ccc35138fd 100644
--- a/test/js/samples/css-shadow-dom-keyframes/expected.js
+++ b/test/js/samples/css-shadow-dom-keyframes/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteElement, createElement, detachNode, init, insert, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteElement, createElement, detachNode, init, insert, noop, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var div, current;
diff --git a/test/js/samples/debug-empty/expected.js b/test/js/samples/debug-empty/expected.js
index 9bc95aa300..1dd048bcf7 100644
--- a/test/js/samples/debug-empty/expected.js
+++ b/test/js/samples/debug-empty/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponentDev, addLoc, append, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponentDev, addLoc, append, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 const file = undefined;
 
diff --git a/test/js/samples/debug-foo-bar-baz-things/expected.js b/test/js/samples/debug-foo-bar-baz-things/expected.js
index 0875f766d7..e5db443057 100644
--- a/test/js/samples/debug-foo-bar-baz-things/expected.js
+++ b/test/js/samples/debug-foo-bar-baz-things/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponentDev, addLoc, append, createElement, createText, destroyEach, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponentDev, addLoc, append, createElement, createText, destroyEach, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 const file = undefined;
 
diff --git a/test/js/samples/debug-foo/expected.js b/test/js/samples/debug-foo/expected.js
index 15fbd99515..eecd79c38d 100644
--- a/test/js/samples/debug-foo/expected.js
+++ b/test/js/samples/debug-foo/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponentDev, addLoc, append, createElement, createText, destroyEach, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponentDev, addLoc, append, createElement, createText, destroyEach, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 const file = undefined;
 
diff --git a/test/js/samples/debug-ssr-foo/expected.js b/test/js/samples/debug-ssr-foo/expected.js
index db9b35477b..afad023a3f 100644
--- a/test/js/samples/debug-ssr-foo/expected.js
+++ b/test/js/samples/debug-ssr-foo/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { create_ssr_component, debug, each, escape } from "svelte/internal.js";
+import { create_ssr_component, debug, each, escape } from "svelte/internal";
 
 const SvelteComponent = create_ssr_component(($$result, $$props, $$bindings, $$slots) => {
 	let { things, foo } = $$props;
diff --git a/test/js/samples/deconflict-builtins/expected.js b/test/js/samples/deconflict-builtins/expected.js
index 34488cc169..75fd699f2d 100644
--- a/test/js/samples/deconflict-builtins/expected.js
+++ b/test/js/samples/deconflict-builtins/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, createComment, createElement, createText, destroyEach, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, createComment, createElement, createText, destroyEach, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 function get_each_context(ctx, list, i) {
 	const child_ctx = Object.create(ctx);
diff --git a/test/js/samples/deconflict-globals/expected.js b/test/js/samples/deconflict-globals/expected.js
index 768c03e023..28f0013dec 100644
--- a/test/js/samples/deconflict-globals/expected.js
+++ b/test/js/samples/deconflict-globals/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, flush, init, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, flush, init, noop, run, safe_not_equal } from "svelte/internal";
 import { onMount } from "svelte";
 
 function create_fragment(component, ctx) {
diff --git a/test/js/samples/dev-warning-missing-data-computed/expected.js b/test/js/samples/dev-warning-missing-data-computed/expected.js
index 76893018d1..82db1b23d2 100644
--- a/test/js/samples/dev-warning-missing-data-computed/expected.js
+++ b/test/js/samples/dev-warning-missing-data-computed/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponentDev, addLoc, append, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponentDev, addLoc, append, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 const file = undefined;
 
diff --git a/test/js/samples/do-use-dataset/expected.js b/test/js/samples/do-use-dataset/expected.js
index b7e0e38dc4..45a433a52f 100644
--- a/test/js/samples/do-use-dataset/expected.js
+++ b/test/js/samples/do-use-dataset/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var div0, text, div1, current;
diff --git a/test/js/samples/dont-use-dataset-in-legacy/expected.js b/test/js/samples/dont-use-dataset-in-legacy/expected.js
index 38fa59d4e3..77ad33739e 100644
--- a/test/js/samples/dont-use-dataset-in-legacy/expected.js
+++ b/test/js/samples/dont-use-dataset-in-legacy/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal, setAttribute } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal, setAttribute } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var div0, text, div1, current;
diff --git a/test/js/samples/dont-use-dataset-in-svg/expected.js b/test/js/samples/dont-use-dataset-in-svg/expected.js
index 7f53da9b1d..3caed4ad32 100644
--- a/test/js/samples/dont-use-dataset-in-svg/expected.js
+++ b/test/js/samples/dont-use-dataset-in-svg/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, createSvgElement, detachNode, flush, init, insert, run, safe_not_equal, setAttribute } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, createSvgElement, detachNode, flush, init, insert, run, safe_not_equal, setAttribute } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var svg, g0, g1, current;
diff --git a/test/js/samples/dynamic-import/expected.js b/test/js/samples/dynamic-import/expected.js
index 1d2b58c23f..80775a2fb1 100644
--- a/test/js/samples/dynamic-import/expected.js
+++ b/test/js/samples/dynamic-import/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, init, mount_component, noop, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, init, mount_component, noop, safe_not_equal } from "svelte/internal";
 import LazyLoad from "./LazyLoad.html";
 
 function create_fragment(component, ctx) {
diff --git a/test/js/samples/each-block-changed-check/expected.js b/test/js/samples/each-block-changed-check/expected.js
index d4e528c469..e2a0900cc5 100644
--- a/test/js/samples/each-block-changed-check/expected.js
+++ b/test/js/samples/each-block-changed-check/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, createElement, createText, destroyEach, detachAfter, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, createElement, createText, destroyEach, detachAfter, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 function get_each_context(ctx, list, i) {
 	const child_ctx = Object.create(ctx);
diff --git a/test/js/samples/each-block-keyed-animated/expected.js b/test/js/samples/each-block-keyed-animated/expected.js
index 9b6bf69e6a..17dcc7bdd7 100644
--- a/test/js/samples/each-block-keyed-animated/expected.js
+++ b/test/js/samples/each-block-keyed-animated/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, blankObject, createComment, createElement, createText, detachNode, fixAndOutroAndDestroyBlock, fixPosition, flush, init, insert, run, safe_not_equal, setData, updateKeyedEach, wrapAnimation } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, blankObject, createComment, createElement, createText, detachNode, fixAndOutroAndDestroyBlock, fixPosition, flush, init, insert, run, safe_not_equal, setData, updateKeyedEach, wrapAnimation } from "svelte/internal";
 
 function get_each_context(ctx, list, i) {
 	const child_ctx = Object.create(ctx);
diff --git a/test/js/samples/each-block-keyed/expected.js b/test/js/samples/each-block-keyed/expected.js
index c6cc65ae44..86cd56d3c7 100644
--- a/test/js/samples/each-block-keyed/expected.js
+++ b/test/js/samples/each-block-keyed/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, blankObject, createComment, createElement, createText, destroyBlock, detachNode, flush, init, insert, run, safe_not_equal, setData, updateKeyedEach } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, blankObject, createComment, createElement, createText, destroyBlock, detachNode, flush, init, insert, run, safe_not_equal, setData, updateKeyedEach } from "svelte/internal";
 
 function get_each_context(ctx, list, i) {
 	const child_ctx = Object.create(ctx);
diff --git a/test/js/samples/event-modifiers/expected.js b/test/js/samples/event-modifiers/expected.js
index 7050f20f0f..edb933ce31 100644
--- a/test/js/samples/event-modifiers/expected.js
+++ b/test/js/samples/event-modifiers/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, addListener, append, createElement, createText, detachNode, init, insert, noop, preventDefault, run, run_all, safe_not_equal, stopPropagation } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, addListener, append, createElement, createText, detachNode, init, insert, noop, preventDefault, run, run_all, safe_not_equal, stopPropagation } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var div, button0, text1, button1, text3, button2, current, dispose;
diff --git a/test/js/samples/head-no-whitespace/expected.js b/test/js/samples/head-no-whitespace/expected.js
index 4b6d2a1b9f..a7c076ba95 100644
--- a/test/js/samples/head-no-whitespace/expected.js
+++ b/test/js/samples/head-no-whitespace/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, createElement, detachNode, init, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, createElement, detachNode, init, noop, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var meta0, meta1, current;
diff --git a/test/js/samples/if-block-no-update/expected.js b/test/js/samples/if-block-no-update/expected.js
index 554392af4b..6c0752b451 100644
--- a/test/js/samples/if-block-no-update/expected.js
+++ b/test/js/samples/if-block-no-update/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createComment, createElement, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createComment, createElement, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal";
 
 // (3:0) {:else}
 function create_else_block(component, ctx) {
diff --git a/test/js/samples/if-block-simple/expected.js b/test/js/samples/if-block-simple/expected.js
index da53b9b6ae..28ef59efd0 100644
--- a/test/js/samples/if-block-simple/expected.js
+++ b/test/js/samples/if-block-simple/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createComment, createElement, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createComment, createElement, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal";
 
 // (1:0) {#if foo}
 function create_if_block(component, ctx) {
diff --git a/test/js/samples/inline-style-optimized-multiple/expected.js b/test/js/samples/inline-style-optimized-multiple/expected.js
index 1add4c0b5d..3f4240ee4e 100644
--- a/test/js/samples/inline-style-optimized-multiple/expected.js
+++ b/test/js/samples/inline-style-optimized-multiple/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createElement, detachNode, flush, init, insert, run, safe_not_equal, setStyle } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createElement, detachNode, flush, init, insert, run, safe_not_equal, setStyle } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var div, current;
diff --git a/test/js/samples/inline-style-optimized-url/expected.js b/test/js/samples/inline-style-optimized-url/expected.js
index 74e4ce3433..3a14088491 100644
--- a/test/js/samples/inline-style-optimized-url/expected.js
+++ b/test/js/samples/inline-style-optimized-url/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createElement, detachNode, flush, init, insert, run, safe_not_equal, setStyle } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createElement, detachNode, flush, init, insert, run, safe_not_equal, setStyle } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var div, current;
diff --git a/test/js/samples/inline-style-optimized/expected.js b/test/js/samples/inline-style-optimized/expected.js
index 21d07e81fc..27774b1018 100644
--- a/test/js/samples/inline-style-optimized/expected.js
+++ b/test/js/samples/inline-style-optimized/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createElement, detachNode, flush, init, insert, run, safe_not_equal, setStyle } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createElement, detachNode, flush, init, insert, run, safe_not_equal, setStyle } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var div, current;
diff --git a/test/js/samples/inline-style-unoptimized/expected.js b/test/js/samples/inline-style-unoptimized/expected.js
index 25e4f65189..8827c97897 100644
--- a/test/js/samples/inline-style-unoptimized/expected.js
+++ b/test/js/samples/inline-style-unoptimized/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var div0, text, div1, div1_style_value, current;
diff --git a/test/js/samples/input-files/expected.js b/test/js/samples/input-files/expected.js
index 86fa171983..acfc8c3866 100644
--- a/test/js/samples/input-files/expected.js
+++ b/test/js/samples/input-files/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, addListener, createElement, detachNode, flush, init, insert, run, safe_not_equal, setAttribute } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, addListener, createElement, detachNode, flush, init, insert, run, safe_not_equal, setAttribute } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var input, input_updating = false, current, dispose;
diff --git a/test/js/samples/input-range/expected.js b/test/js/samples/input-range/expected.js
index e7719faaae..4f1d79991c 100644
--- a/test/js/samples/input-range/expected.js
+++ b/test/js/samples/input-range/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, addListener, createElement, detachNode, flush, init, insert, run, run_all, safe_not_equal, setAttribute, toNumber } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, addListener, createElement, detachNode, flush, init, insert, run, run_all, safe_not_equal, setAttribute, toNumber } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var input, current, dispose;
diff --git a/test/js/samples/input-without-blowback-guard/expected.js b/test/js/samples/input-without-blowback-guard/expected.js
index 12d3fb41a4..8dc8db1088 100644
--- a/test/js/samples/input-without-blowback-guard/expected.js
+++ b/test/js/samples/input-without-blowback-guard/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, addListener, createElement, detachNode, flush, init, insert, run, safe_not_equal, setAttribute } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, addListener, createElement, detachNode, flush, init, insert, run, safe_not_equal, setAttribute } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var input, current, dispose;
diff --git a/test/js/samples/instrumentation-script-if-no-block/expected.js b/test/js/samples/instrumentation-script-if-no-block/expected.js
index 8ccf2cbbb5..e58b54f626 100644
--- a/test/js/samples/instrumentation-script-if-no-block/expected.js
+++ b/test/js/samples/instrumentation-script-if-no-block/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, addListener, append, createElement, createText, detachNode, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, addListener, append, createElement, createText, detachNode, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var button, text1, p, text2, text3, current, dispose;
diff --git a/test/js/samples/instrumentation-script-x-equals-x/expected.js b/test/js/samples/instrumentation-script-x-equals-x/expected.js
index e34525d978..6b941101d6 100644
--- a/test/js/samples/instrumentation-script-x-equals-x/expected.js
+++ b/test/js/samples/instrumentation-script-x-equals-x/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, addListener, append, createElement, createText, detachNode, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, addListener, append, createElement, createText, detachNode, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var button, text1, p, text2, text3_value = ctx.things.length, text3, current, dispose;
diff --git a/test/js/samples/instrumentation-template-if-no-block/expected.js b/test/js/samples/instrumentation-template-if-no-block/expected.js
index 5c8742f123..bbf81ac336 100644
--- a/test/js/samples/instrumentation-template-if-no-block/expected.js
+++ b/test/js/samples/instrumentation-template-if-no-block/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, addListener, append, createElement, createText, detachNode, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, addListener, append, createElement, createText, detachNode, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var button, text1, p, text2, text3, current, dispose;
diff --git a/test/js/samples/instrumentation-template-x-equals-x/expected.js b/test/js/samples/instrumentation-template-x-equals-x/expected.js
index 15a1994cf5..759cafbb51 100644
--- a/test/js/samples/instrumentation-template-x-equals-x/expected.js
+++ b/test/js/samples/instrumentation-template-x-equals-x/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, addListener, append, createElement, createText, detachNode, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, addListener, append, createElement, createText, detachNode, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var button, text1, p, text2, text3_value = ctx.things.length, text3, current, dispose;
diff --git a/test/js/samples/legacy-input-type/expected.js b/test/js/samples/legacy-input-type/expected.js
index 5dde731662..05c739d846 100644
--- a/test/js/samples/legacy-input-type/expected.js
+++ b/test/js/samples/legacy-input-type/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, createElement, detachNode, init, insert, noop, run, safe_not_equal, setInputType } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, createElement, detachNode, init, insert, noop, run, safe_not_equal, setInputType } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var input, current;
diff --git a/test/js/samples/media-bindings/expected.js b/test/js/samples/media-bindings/expected.js
index d934df9f41..f3c888ccb9 100644
--- a/test/js/samples/media-bindings/expected.js
+++ b/test/js/samples/media-bindings/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, addListener, add_render_callback, createElement, detachNode, flush, init, insert, run, run_all, safe_not_equal, timeRangesToArray } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, addListener, add_render_callback, createElement, detachNode, flush, init, insert, run, run_all, safe_not_equal, timeRangesToArray } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var audio, audio_is_paused = true, audio_updating = false, audio_animationframe, current, dispose;
diff --git a/test/js/samples/non-imported-component/expected.js b/test/js/samples/non-imported-component/expected.js
index 195441148e..2c2fa6a80e 100644
--- a/test/js/samples/non-imported-component/expected.js
+++ b/test/js/samples/non-imported-component/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, callAfter, createText, detachNode, init, insert, mount_component, noop, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, callAfter, createText, detachNode, init, insert, mount_component, noop, safe_not_equal } from "svelte/internal";
 import Imported from "Imported.html";
 
 function create_fragment(component, ctx) {
diff --git a/test/js/samples/select-dynamic-value/expected.js b/test/js/samples/select-dynamic-value/expected.js
index a143d8a6c3..0533703f1c 100644
--- a/test/js/samples/select-dynamic-value/expected.js
+++ b/test/js/samples/select-dynamic-value/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, createElement, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, createElement, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var select, option0, option1, select_value_value, current;
diff --git a/test/js/samples/setup-method/expected.js b/test/js/samples/setup-method/expected.js
index f84db159ea..e5c2b1b541 100644
--- a/test/js/samples/setup-method/expected.js
+++ b/test/js/samples/setup-method/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, init, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, init, noop, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var current;
diff --git a/test/js/samples/ssr-no-oncreate-etc/expected.js b/test/js/samples/ssr-no-oncreate-etc/expected.js
index 73824daca8..45f86d3682 100644
--- a/test/js/samples/ssr-no-oncreate-etc/expected.js
+++ b/test/js/samples/ssr-no-oncreate-etc/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { create_ssr_component } from "svelte/internal.js";
+import { create_ssr_component } from "svelte/internal";
 import { onDestroy, onMount } from "svelte";
 
 function preload(input) {
diff --git a/test/js/samples/ssr-preserve-comments/expected.js b/test/js/samples/ssr-preserve-comments/expected.js
index dc9f63de4d..e910b63df2 100644
--- a/test/js/samples/ssr-preserve-comments/expected.js
+++ b/test/js/samples/ssr-preserve-comments/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { create_ssr_component } from "svelte/internal.js";
+import { create_ssr_component } from "svelte/internal";
 
 const SvelteComponent = create_ssr_component(($$result, $$props, $$bindings, $$slots) => {
 	return `<div>content</div>
diff --git a/test/js/samples/svg-title/expected.js b/test/js/samples/svg-title/expected.js
index a442194556..80b87f0fe7 100644
--- a/test/js/samples/svg-title/expected.js
+++ b/test/js/samples/svg-title/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, createSvgElement, createText, detachNode, init, insert, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, createSvgElement, createText, detachNode, init, insert, noop, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var svg, title, text, current;
diff --git a/test/js/samples/title/expected.js b/test/js/samples/title/expected.js
index 993093d4c4..69f412640a 100644
--- a/test/js/samples/title/expected.js
+++ b/test/js/samples/title/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, flush, init, noop, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, flush, init, noop, run, safe_not_equal } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var title_value, current;
diff --git a/test/js/samples/use-elements-as-anchors/expected.js b/test/js/samples/use-elements-as-anchors/expected.js
index 2a1de7945f..8ef798cd67 100644
--- a/test/js/samples/use-elements-as-anchors/expected.js
+++ b/test/js/samples/use-elements-as-anchors/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, append, createComment, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, append, createComment, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal } from "svelte/internal";
 
 // (2:1) {#if a}
 function create_if_block_4(component, ctx) {
diff --git a/test/js/samples/window-binding-scroll/expected.js b/test/js/samples/window-binding-scroll/expected.js
index 3c3ea3d74a..fee92a8d45 100644
--- a/test/js/samples/window-binding-scroll/expected.js
+++ b/test/js/samples/window-binding-scroll/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent as SvelteComponent_1, add_render_callback, append, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal.js";
+import { SvelteComponent as SvelteComponent_1, add_render_callback, append, createElement, createText, detachNode, flush, init, insert, run, safe_not_equal, setData } from "svelte/internal";
 
 function create_fragment(component, ctx) {
 	var window_updating = false, clear_window_updating = function() { window_updating = false; }, window_updating_timeout, p, text0, text1, current;
diff --git a/test/runtime/index.js b/test/runtime/index.js
index 58ef9d8734..a230e8f571 100644
--- a/test/runtime/index.js
+++ b/test/runtime/index.js
@@ -233,7 +233,7 @@ describe("runtime", () => {
 				{
 					resolveId: (importee, importer) => {
 						if (importee.startsWith('svelte/')) {
-							return importee.replace('svelte', process.cwd());
+							return importee.replace('svelte', process.cwd()) + '.mjs';
 						}
 					}
 				}