【问题】
后台做了访问PDF文档需验证前端带过来的token，前端vue-admin-template查看pdf文档，使用的是import pdf from 'vue-pdf'，axios在main.js中设置withCredentials后可以带上cookie，然后pdf用到的promise异步怎么携带cookie始终不清楚，查看官方文档【参考网址】中有
Public static methods
createLoadingTask(src[, options])
src: see :src prop
options: an object of options. This function creates a PDFJS loading task that can be used and reused as :src property.
The loading task is a promise that resolves with the PDFJS pdf document that exposes the numPages property (see example below).
beware: when the component is destroyed, the object returned by createLoadingTask() become invalid.
Supported options:
onPassword: Callback that's called when a password protected PDF is being opened.
onProgress: Callback return loading progress.
withCredentials: Wheter or not to send cookies in the fetch request.中也有withCredentials，设置后应该就可以带上cookie，故修改代码如下
#原代码
this.pdfsrc = pdf.createLoadingTask(this.src)
#修改后如下
this.pdfsrc = pdf.createLoadingTask(this.src, {withCredentials:true})【解决办法】
【参考网址】
GitHub - FranckFreiburger/vue-pdf: vue.js pdf viewer
