Borislav Hadzhiev
Tue Mar 22 2022·2 min read
Photo by Qi Bin
The error "Property 'innerText' does not exist on type 'Element'" occurs when
we try to access the innerText
property on an element that has a type of
Element
. To solve the error, use a type assertion to type the element as
HTMLElement
before accessing the property.
This is the index.html
file for the examples in this article.
<!DOCTYPE html> <html> <head> <meta charset="UTF-8" /> </head> <body> <div id="box">Hello world</div> <script src="./src/index.ts"></script> </body> </html>
And here is an example of how the error occurs in the index.ts
file.
// 👇️ const box: Element | null const box = document.querySelector('#box'); if (box != null) { // ⛔️ Property 'innerText' does not exist on type 'Element'.ts(2339) box.innerText = 'New text'; }
The reason we got the error is because the return type of the
document.querySelector
method is Element | null
and the innerText
property doesn't exist in the
Element
type.
To solve the error, use a type assertion to type the element as an
HTMLElement
.
const box = document.querySelector('#box') as HTMLElement | null; if (box != null) { box.innerText = 'New text'; }
If you used the
document.getElementsByClassName
method, type the collection as HTMLCollectionOf<HTMLElement>
.
// 👇️ with getElementsByClassName // type as HTMLCollectionOf<HTMLElement> const boxes = document.getElementsByClassName( 'box', ) as HTMLCollectionOf<HTMLElement>; for (let i = 0; i < boxes.length; i++) { boxes[i].innerText = 'New Text'; }
Type assertions are used when we have information about the type of a value that TypeScript can't know about.
box
variable stores anHTMLElement
or a null
value and not to worry about it.We used a
union type
to specify that the variable could still be null
, because if an HTML element
with the provided selector does not exist in the DOM, the querySelector()
method returns a null
value.
We used a simple if
statement that serves as a
type guard
to make sure the box
variable doesn't store a null
value before accessing
its innerText
property.
const box = document.querySelector('#box') as HTMLElement | null; // 👉️ box has type HTMLElement or null here if (box != null) { // 👉️ box has type HTMLElement here box.innerText = 'New text'; }
box
variable has a type of HTMLElement
in the if
block and allows us to directly access its innerText
property.It's always a best practice to include null
in the type assertion, because the
querySelector
method would return null
if no element with the provided
selector was found.