refactor(compiler): extract isStaticExp util

packages/compiler-ssr/src/transforms/ssrTransformElement.ts

@@ -24,7 +24,8 @@ import {
   MERGE_PROPS,
   isBindKey,
   createSequenceExpression,
-  InterpolationNode
+  InterpolationNode,
+  isStaticExp
 } from '@vue/compiler-dom'
 import {
   escapeHtml,
@@ -194,7 +195,7 @@ export const ssrTransformElement: NodeTransform = (node, context) => {
             }
             for (let j = 0; j < props.length; j++) {
               const { key, value } = props[j]
-              if (key.type === NodeTypes.SIMPLE_EXPRESSION && key.isStatic) {
+              if (isStaticExp(key)) {
                 let attrName = key.content
                 // static key attr
                 if (attrName === 'class') {