refactor(client): add default type fallback api for (#6644)

packages/core/client/src/schema-component/antd/variable/Input.tsx

@@ -26,12 +26,13 @@ import { Json } from '../input';
 const JT_VALUE_RE = /^\s*{{\s*([^{}]+)\s*}}\s*$/;
 
 type ParseOptions = {
+  defaultTypeOnNull?: string;
   stringToDate?: boolean;
 };
 
 function parseValue(value: any, options: ParseOptions = {}): string | string[] {
   if (value == null) {
-    return 'null';
+    return options.defaultTypeOnNull ?? 'null';
   }
   const type = typeof value;
   if (type === 'string') {

packages/plugins/@nocobase/plugin-workflow-delay/src/client/DelayInstruction.tsx

@@ -57,6 +57,9 @@ export default class extends Instruction {
             placeholder: `{{t("Duration", { ns: "${NAMESPACE}" })}}`,
             useTypedConstant: [['number', { min: 1 }]],
             nullable: false,
+            parseOptions: {
+              defaultTypeOnNull: 'number',
+            },
           },
           default: 1,
           required: true,