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Here's the code:
const test = Array.from(document.getElementsByClassName('mat-form-field-infix'));
test.forEach((element) => {
element.outerHTML = '<div class="good-day-today" style="width: 0px;"></div>'; // Please note that this line works fine!
element.style.padding = '10px';
element.style.borderTop = '0';
Error I get when compiled:
ERROR in src/app//.component.ts(101,21): error TS2339: Property
'style' does not exist on type 'Element'.
src/app//.component.ts(102,21): error TS2339: Property 'style'
does not exist on type 'Element'.
How can I fix it?
I tried to remove the Array.from...
part, tried to use for of
and for in
, tried as any
, but above is the way I have to do it.
–
–
You need a typecast:
Array.from(document.getElementsByClassName('mat-form-field-infix') as HTMLCollectionOf<HTMLElement>)
That's because getElementsByClassName
only returns HTMLCollection<Element>
, and Element
does not have a style
property. The HTMLElement
however does implement it via it's ElementCSSInlineStyle
extended interface.
Note that this typecast is typesafe in the way that every Element
is either a HTMLElement
or an SVGElement
, and I hope that your SVG Elements don't have a class.
–
Another option is to use querySelectorAll
and a type parameter. getElementsByClassName
is not generic, but querySelectorAll
is - you can just pass the type of the elements that will be selected, like this:
const test = document.querySelectorAll<HTMLElement>('.mat-form-field-infix');
This doesn't require any type casting, and it will allow you to use forEach
immediately, rather than converting it to an array first. (getElementsByClassName
returns an HTMLCollection, which does not have a forEach
method; querySelectorAll
returns a NodeList
, which does have a forEach
method, at least on somewhat up-to-date browsers. To support ancient browsers too, you'll need a polyfill, or convert it to an array first.)
If you happen to just need a single element, you can use querySelector
, which is generic as well:
const elm = document.querySelector<HTMLElement>('.foo')!;
elm.style.padding = '10px';
Another benefit of querySelectorAll
(and querySelector
) over the many other options is that they accept CSS selector strings, which can be far more flexible and precise. For example, the selector string
.container > input:checked
will select children of <div class="container">
which are <input>
s and are checked.
A workaround could be doing something like this:
element["style"].padding = '10px';
element["style"].borderTop = '0';
Maybe it's not the best solution, but it should work, I used it multiple times :)
–
When you set the outerHTML, you're destroying the original element that was there. So, your styling doesn't work.
You'll notice that if you change it to set innerHTML, your styling does work.
This does not do the same exact thing, but I hope it points you in the right direction.
const test = Array.from(document.getElementsByClassName('mat-form-field-infix'));
test.forEach((element) => {
element.innerHTML = '<div class="good-day-today" style="width: 0px;"></div>'; // Please note that this line works fine!
element.style.padding = '10px';
element.style.borderTop = '0';
I was also facing a similar type of issue while doing
document.querySelectorAll(".<className>");
so instead of adding the style property, I simply got around it by just adding another class.
example:
//css file
.<classname> {
display: none;
.<classname>.show {
display: flex;
//ts file
elements.forEach((ele, index) => {
const errors = something.length;
if (index < errors) {
ele.classList.add("show");
} else {
ele.classList.remove("show");
I think I found a way easier method:
Just create an index.d.ts file and add:
interface Element {
style: CSSStyleDeclaration
The answer from Jonas Wilms is not totally right (anymore?).
While I suspect that type casting will not cause any problems in this case, I would still avoid type casting whenever possible. In this case, you can avoid type casting with instanceof narrowing:
const test = Array.from(
document.getElementsByClassName('mat-form-field-infix')
test.forEach((element) => {
if (!(element instanceof HTMLElement)) {
return
element.outerHTML =
'<div class="good-day-today" style="width: 0px;"></div>' // Please note that this line works fine!
element.style.padding = '10px'
element.style.borderTop = '0'
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