Sometimes, we want to clear text selection with JavaScript.
In this article, we’ll look at how to clear text selection with JavaScript.
To clear text selection with JavaScript, we can use the empty method.
For instance, we write
window.getSelection().empty();
to call getSelection to get the select text in an object.
Then we call empty to clear the selection.
To clear text selection with JavaScript, we can use the empty method.
Sometimes, we want to fix JavaScript map function return undefined.
In this article, we’ll look at how to fix JavaScript map function return undefined.
To fix JavaScript map function return undefined, we use filter instead of map for filtering.
For instance, we write
const arr = ["a", "b", 1];
const results = arr.filter((item) => {
return typeof item === "string";
});
to call arr.filter with a callback that returns if the item in arr has type 'string'.
If it is, we add it to the returned array.
Otherwise, we skip it.
To fix JavaScript map function return undefined, we use filter instead of map for filtering.
Sometimes, we want to detect if input is focused with JavaScript
In this article, we’ll look at how to detect if input is focused with JavaScript
To detect if input is focused with JavaScript, we can check is document.activeElement is the input.
For instance, we write
e.target === document.activeElement
in an event handler to check if the element that triggered the event, which is e.target is the same as document.activeElement.
document.activeElement is the element that has focus on the page.
To detect if input is focused with JavaScript, we can check is document.activeElement is the input.
Sometimes, we want to fix property ‘catch’ does not exist on type ‘Observable’ with Rxjs.
In this article, we’ll look at how to fix property ‘catch’ does not exist on type ‘Observable’ with Rxjs.
To fix property ‘catch’ does not exist on type ‘Observable’ with Rxjs, we can use the catchError function.
For instance, we write
import { Observable } from "rxjs";
import { catchError } from "rxjs/operators";
//...
this.http.request(method, url, options).pipe(
catchError((err: HttpErrorResponse) => {
//...
})
);
to call request with pipe to pipe the request results.
Then we call catchError in pipe to catch any errors are returned by the observable returned by request.
To fix property ‘catch’ does not exist on type ‘Observable’ with Rxjs, we can use the catchError function.
Sometimes, we want to add a button that refreshes the page on click with JavaScript.
In this article, we’ll look at how to add a button that refreshes the page on click with JavaScript.
To add a button that refreshes the page on click with JavaScript, we add a click listener to the button.
For instance, we write
<button class="refresh-button">Refresh!</button>
to add a button.
Then we write
const refreshButton = document.querySelector(".refresh-button");
const refreshPage = () => {
location.reload();
};
refreshButton.addEventListener("click", refreshPage);
to select the button with querySelector.
And then we call addEventListener on the button to add refreshPage as the click event listener.
In refreshPage, we call location.reload to reload the page when we click on the button.
To add a button that refreshes the page on click with JavaScript, we add a click listener to the button.