feat: with & for in render tag, closes #195

src/util/collection.ts

@@ -0,0 +1,8 @@
+import { isString, isObject, isArray } from './underscore'
+
+export function toCollection (val: any) {
+  if (isArray(val)) return val
+  if (isString(val) && val.length > 0) return [val]
+  if (isObject(val)) return Object.keys(val).map((key) => [key, val[key]])
+  return []
+}