error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
tests/cases/compiler/a.js(1,1): error TS8003: 'export =' can only be used in TypeScript files.


!!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
==== tests/cases/compiler/a.js (1 errors) ====
    export = b;
    ~~~~~~~~~~~
!!! error TS8003: 'export =' can only be used in TypeScript files.