any Property 'getElementById' does not exist on type 'HTMLGdsSwimlaneElement' code example
Example 1: Property 'value' does not exist on type 'HTMLElement'.
document.getElementById() returns the type HTMLElement which does not contain a value property.
The subtype HTMLInputElement does however contain the value property.
So a solution is to cast the result of getElementById() to HTMLInputElement like this:
var inputValue = (<HTMLInputElement>document.getElementById(elementId)).value;
<> is the casting operator in typescript.
See TypeScript: casting HTMLElement: https://fireflysemantics.medium.com/casting-htmlelement-to-htmltextareaelement-in-typescript-f047cde4b4c3
The resulting javascript from the line above looks like this:
inputValue = (document.getElementById(elementId)).value;
i.e. containing no type information.
Example 2: Property 'on' does not exist on type 'HTMLElement'.
To prevent this error you can write:
var plotDiv: any = document.getElementById('myDiv');
plotDiv.on('plotly_relayout', ...
document.getElementById('myDiv') return HTMLElement. This type doesn't contain method
on because this method is added within plotly-latest.min.js. So in order to silence
the typescript warning you can explicity say compile not to check types for plotDiv
Another way is create type definition like:
interface PlotHTMLElement extends HTMLElement {
on(eventName: string, handler: Function): void;
}
var plotDiv = <PlotHTMLElement>document.getElementById('myDiv')
plotDiv.on('plotly_relayout', function() {
});