fail if we find any async functions

index.mjs

@@ -197,6 +197,9 @@ function renderTemplate({ name, elements, attrs=[], state={} }) {
     ? templateRenderFunction
     : elements[name]
 
+  if (template.constructor.name ==='AsyncFunction')
+    throw Error(`illegal_async_function: ${name} must be a Function not an AsyncFunction`)
+
   if (template && typeof template === 'function') {
     return fragment(template({ html: render, state }))
   }

package.json

@@ -8,9 +8,9 @@
   "type": "module",
   "main": "index.mjs",
   "scripts": {
-    "test": "tape ./test/enhance.test.mjs | tap-arc"
+    "test": "tape ./test/*.test.mjs | tap-arc"
   },
-  "keywords": [],
+  "keywords": ["webcomponents", "customelements", "ssr"],
   "author": "kj <[email protected]>",
   "license": "Apache-2.0",
   "devDependencies": {

test/illegal_async_function.test.mjs

@@ -0,0 +1,19 @@
+import test from 'tape'
+import enhance from '../index.mjs'
+
+test('cannot async', t=> {
+  let html = enhance({
+    elements: {
+      'el-hi': async function wups() {
+        return 'wat'
+      }
+    }
+  })
+  try {
+    let res = html`<el-hi></el-hi>`
+  }
+  catch (e) {
+    t.ok(e.message.startsWith('illegal_async'), e.message)
+  }
+  t.end()
+})