如何在打字稿中使用reset（）、. value和其他DOM键？

Question

So I'm using typescript for basic funkcionality, however it refuses to compile because of the following error

src/app.ts:46:38 - error TS2339: Property 'value' does not exist on type 'HTMLElement'.

46   return document.getElementById(id).value

I have es2017 as a target, therefore I have read that it includes dom libraries, however I still cannot make it work.

Is there a way to use .value, reset() and other dom methods or at least make compiler ignore this error?

Answer 1

For document.getElementById(id) , TypeScript can't know for sure that the element returned will of the type HTMLInputElement . You will have to use an assertion if you want to infor typescript about what your html will contain (and therefore dom will return):

return (document.getElementById(id) as HTMLInputElement).value