Give a clearer error message when rendering into null/undefined (#2661)

lit · Mar 25, 2022 · 9a3a38c · 9a3a38c
1 parent 1d51ed8
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diff --git a/.changeset/tidy-lies-admire.md b/.changeset/tidy-lies-admire.md
@@ -0,0 +1,6 @@
+---
+'lit-html': patch
+'lit': patch
+---
+
+Give a clearer error message when rendering into null/undefined
diff --git a/packages/lit-html/src/lit-html.ts b/packages/lit-html/src/lit-html.ts
@@ -637,6 +637,13 @@ export const render = (
   container: HTMLElement | DocumentFragment,
   options?: RenderOptions
 ): RootPart => {
+  if (DEV_MODE && container == null) {
+    // Give a clearer error message than
+    //     Uncaught TypeError: Cannot read properties of null (reading
+    //     '_$litPart$')
+    // which reads like an internal Lit error.
+    throw new TypeError(`The container to render into may not be ${container}`);
+  }
   const renderId = DEV_MODE ? debugLogRenderId++ : 0;
   const partOwnerNode = options?.renderBefore ?? container;
   // This property needs to remain unminified.