Typescript: Property 'offsetTop' does not exist on type 'Element'.ts(2339)

[TangMonk]

TypeScript Version: 3.6.4

Code

document.querySelector('.page').offsetTop

[MartinJohns]

This is correct. First of all, the result can be null, so if you have strictNullChecks enabled you need to perform a null check first:

const element = document.querySelector('.page');
if (element !== null) { ... }

Secondly, the return type is Element, and Element has no property offsetTop. You likely expect it to return a HTMLElement, but this is not obvious to the compiler because it could just as well be a SVGElement.

To fix this you can either use a type-assertion: element as HTMLElement

Or actively perform a runtime check: if (element instanceof HTMLElement) {}

---

Everything works as it should. Please also take note of the issue template.