diff --git a/component.js b/component.js
index 62e616d..e8e51d9 100644
--- a/component.js
+++ b/component.js
@@ -378,7 +378,7 @@ export const defineListComponent = createComponentDefiner(() => {
         component.removeChild(prevChild)
       }
       // insert remaining
-      component.insertBefore(dom.fragment(insert.slice(insertStart).map(insState => {
+      component.insertBefore(dom.fragment(insert.slice(insertStart).map(/** @param {any} insState */ insState => {
         const el = new Item()
         el.setState(insState)
         return el
diff --git a/environment.js b/environment.js
index 3127448..5ebf4c3 100644
--- a/environment.js
+++ b/environment.js
@@ -94,7 +94,7 @@ export const getParam = (name, defaultVal) =>
 /* c8 ignore next 4 */
 export const getVariable = (name) =>
   isNode
-    ? conditions.undefinedToNull(process.env[name.toUpperCase()])
+    ? conditions.undefinedToNull(process.env[name.toUpperCase().replaceAll('-', '_')])
     : conditions.undefinedToNull(storage.varStorage.getItem(name))
 
 /**
@@ -105,6 +105,17 @@ export const getVariable = (name) =>
 export const getConf = (name) =>
   computeParams().get('--' + name) || getVariable(name)
 
+/**
+ * @param {string} name
+ * @return {string}
+ */
+/* c8 ignore next 4 */
+export const ensureConf = (name) => {
+  const c = getConf(name)
+  if (c == null) throw new Error(`Expected configuration "${name.toUpperCase().replaceAll('-', '_')}"`)
+  return c
+}
+
 /**
  * @param {string} name
  * @return {boolean}