最近在做vue的模板生成工具，发现vue的${}语法与FreeMarker语法冲突，通过对FreeMarker官网文档的查询解决了该问题。

表达式 - FreeMarker 中文官方参考手册 (foofun.cn)

直接确定值

• 字符串

 解决方法：

 问题场景：

原模板：
         toolbarDel(selections){
            _this.$confirm(`此操作将删除所选${selections.length}条数据, 是否继续?`, '提示', {
              confirmButtonText: '确定',
              cancelButtonText: '取消',
              type: 'warning'
            }).then(() => {
              _this.$message({
                type: 'success',
                message: '删除成功!'
              });
              _this.$refs.grid.reload()
            }).catch(() => {
              _this.$message({
                type: 'info',
                message: '已取消删除'
              });          
            });
          }
更改后的模板：
         toolbarDel(selections){
            _this.$confirm(`此操作将删除所选${r"${selections.length}"}条数据, 是否继续?`, '提示', {
              confirmButtonText: '确定',
              cancelButtonText: '取消',
              type: 'warning'
            }).then(() => {
              _this.$message({
                type: 'success',
                message: '删除成功!'
              });
              _this.$refs.grid.reload()
            }).catch(() => {
              _this.$message({
                type: 'info',
                message: '已取消删除'
              });          
            });
          }

错误日志

freemarker.core.InvalidReferenceException: The following has evaluated to null or missing:
==> selections  [in template "grid/index.ftl" at line 97, column 39]

----
Tip: If the failing expression is known to legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??
----

----
FTL stack trace ("~" means nesting-related):
	- Failed at: ${selections.length}  [in template "grid/index.ftl" at line 97, column 37]