Validate helpers

packages/builder/src/components/common/CodeEditor/CodeEditor.svelte

@@ -284,17 +284,19 @@
               return
             }
 
-            const config = validations[helperName]
+            const { arguments: expectedArguments = [] } =
+              validations[helperName]
 
             const providedParams = node.params
-            if (providedParams.length !== config.arguments.length) {
+
+            if (providedParams.length !== expectedArguments.length) {
               diagnostics.push({
                 from,
                 to,
                 severity: "error",
                 message: `Helper "${helperName}" expects ${
-                  config.arguments.length
+                  expectedArguments.length
-                } parameters (${config.arguments.join(", ")}), but got ${
+                } parameters (${expectedArguments.join(", ")}), but got ${
                   providedParams.length
                 }.`,
               })

packages/builder/src/components/common/bindings/BindingPanel.svelte

@@ -110,6 +110,12 @@
       }
       return validations
     }, {}),
+    ...helperOptions.reduce<CodeValidator>((validations, option) => {
+      validations[option.label] = {
+        arguments: option.args,
+      }
+      return validations
+    }, {}),
   }
 
   $: {

packages/builder/src/types/bindings.ts

@@ -12,6 +12,6 @@ export interface BindingCompletionOption extends Completion {
 export type CodeValidator = Record<
   string,
   {
-    arguments: any[]
+    arguments?: any[]
   }
 >