打不出数据库的值，errMsg: RegExp options.regexp should be string instead of undefined;

const db=wx.cloud.database()
let searchKer =''
Page({
onLoad:function(options){
console.log("options",options)
let searchKer = options.searchKer
db.collection('caipu').where({
cainame:db.RegExp({
regexp:searchKer,
options:'i'//不区分大小写
})
})
.get()
.then(res=>{
console.log('搜索成功',res)
})
.catch(res=>{
console.log('搜索失败',res)
})
}
})