Imports must be top level

That is, they must be in the main sequence of instructions that is performed when a module is executed. There is no way to conditionally import something.

This also applies to functions and loops.

If you need to load something dynamically, use the import function, which returns a Promise.

Why?

The TypeScript compiler, along with bundlers like Webpack or ESBuild, rely on static analysis - the process of analyzing a program's code to determine dependencies and optimizations.