Advertisements I have Arrays of objects and needs to loop through it and display it in the DOM. I able to do it with map function. But i getting the error due to lack of providing unique keys for it. Remember, it is not using the component to loop. I just want JSX to loop… Read More How to define keys in React JSX when use Map function

Advertisements I am getting started with Web Components and want to get all elements where the tag name ends in "-component", in order to register them as custom tags. For best performance, I want to use querySelectorAll and not iterate over all elements. However, as you can see in the following example [tag$="-component"] does not… Read More JavaScript querySelector – Select elements when the tag ends in a specified string

Advertisements Came across something I cant find in docs. This #selectedIndex = 0; what does # do? class WcTabPanel extends HTMLElement { static observedAttributes = ["selected-index", "direction"]; #selectedIndex = 0; appears in this example https://codepen.io/ndesmic/pen/mdELqbM >Solution : It means private field. Class fields are public by default, but private class members can be created by… Read More what does # mean in javascript

Advertisements I have a button in my header that has to switch the state of the lateral menu of the page (to know if it has to be shown or not). I found out on Internet how to do so using Class Components, but not with Functional Components, do you have any idea on how… Read More Change the state of another component using functionnal components in React

Advertisements ` Unhandled Runtime Error Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it’s defined in, or you might have mixed up default and named imports. Check the render method of DashboardCards. `… Read More Element type is invalid: expected a string (for built-in components) or a class/function. while trying to render a component