When I build my react project I get an error like this.

export type ExtractRouteOptionalParam<T extends string, U = string | number | boolean> = T extends `${infer Param}?`      
  ? { [k in Param]?: U }
  : T extends `${infer Param}*`
  ? { [k in Param]?: U }

How to solve this?

CodePudding user response：

I am adding an answer for future reference for others.

Yes like others mentioned typescript was the issue.

I upgraded it to the latest version (currently 4.8.3). After upgrading, I had to fix a type issue on my redux saga file and I had to upgrade react-scripts to 4.0.1 to fix the Parsing error: Cannot read properties of undefined (reading 'map').

CodePudding user response：

I meet seem issue on yesterday. And I use typescript version is 3.9.3. I had try version 3.9.10 cannot sovle this problem

CodePudding user response：

I updated typescript version to 4.1.6 and it worked for me. I tried newest version of typescript. It also works, but it doesn't support all the features I need.