fix(compiler): remove empty modifiers

Author: zhiyuanzmj

packages/compiler/src/utils.ts

@@ -300,7 +300,7 @@ export function resolveDirectiveNode(
   if (name.type !== 'JSXNamespacedName' && !argString) {
     const [newName, modifiers] = nameString.split('_')
     nameString = newName
-    argString = `_${modifiers}`
+    modifiers && (argString = `_${modifiers}`)
   }
 
   let modifiers: string[] = []

packages/compiler/test/transforms/__snapshots__/vModel.spec.ts.snap

@@ -23,3 +23,11 @@ exports[`compiler: vModel transform > modifiers > .trim 1`] = `
   return n0
 "
 `;
+
+exports[`compiler: vModel transform > should support simple expression 1`] = `
+"
+  const n0 = t0()
+  _applyTextModel(n0, () => (model), _value => (model = _value))
+  return n0
+"
+`;

packages/compiler/test/transforms/vModel.spec.ts

@@ -18,13 +18,7 @@ const compileWithVModel = makeCompile({
 describe('compiler: vModel transform', () => {
   test('should support simple expression', () => {
     const { code, helpers } = compileWithVModel('<input v-model={model} />')
-    expect(code).toMatchInlineSnapshot(`
-      "
-        const n0 = t0()
-        _applyTextModel(n0, () => (model), _value => (model = _value), { undefined: true })
-        return n0
-      "
-    `)
+    expect(code).toMatchSnapshot()
     expect(helpers).toContain('applyTextModel')
   })