报错原因：
TypeError: Cannot create pr
operty ‘xxx’ on string ‘xxxx’，此类错误是赋值的类型错误，
this.canonicalImage =result.data.item.picList//错误示范，piclist应为对象格式
this.canonicalImage =result.data.item.picList.map(item => {
return {
name: item,
url: item
}
});