Fix "this._recompute is not a function"

Close sveltejs/svelte#2049

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "2.15.1",
+  "version": "2.16.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {

src/compile/render-dom/index.ts

@@ -289,8 +289,6 @@ export default function dom(
 					target.insertBefore(this, anchor);
 				}
 			});
-
-			customElements.define("${component.tag}", ${name});
 		`);
 	} else {
 		builder.addBlock(deindent`
@@ -328,6 +326,10 @@ export default function dom(
 		${immutable && `${name}.prototype._differs = @_differsImmutable;`}
 	`);
 
+	if (component.customElement) {
+		builder.addBlock(`customElements.define("${component.tag}", ${name});`);
+	}
+
 	let result = builder.toString();
 
 	return component.generate(result, options, {

test/cli/samples/custom-element/expected/Main.js

@@ -67,10 +67,10 @@ assign(Main.prototype, {
 	}
 });
 
-customElements.define("my-element", Main);
-
 Main.prototype._recompute = noop;
 
+customElements.define("my-element", Main);
+
 function createElement(name) {
 	return document.createElement(name);
 }

test/js/samples/css-shadow-dom-keyframes/expected.js

@@ -59,5 +59,7 @@ assign(SvelteComponent.prototype, {
 	}
 });
 
+
+
 customElements.define("custom-element", SvelteComponent);
 export default SvelteComponent;