@babel/preset-typescript

[2zH]

• TypeScript and Babel 7(MSDN)
• Babel7 or TypeScript(ts-jest)

[2zH]

First

Babel won’t perform type-checking on TypeScript code; it will only be transforming your code, and it will compile regardless of whether type errors are present.

Second

there are certain constructs that don’t currently compile in Babel 7. Specifically

• namespaces
• bracket style type-assertion/cast syntax regardless of when JSX is enabled (i.e. writing x won’t work even in .ts files if JSX support is turned on, but you can instead write x as Foo).
• enums that span multiple declarations (i.e. enum merging)
• legacy-style import/export syntax (i.e. import foo = require(...) and export = foo)