Because involves data loading problem, need to let imgSign downwards, this function is performed first to imgSign finally returned to a true value,
I here let assigns values to res print, but the res print is undefined, why, is there any other place of the two key words also doesn't work,, then () doesn't work as well,

Async toSign (signType) {
Let res=await this. ImgSign ()
The console. The log (' res' res)
},