Q61. What is scope in javascript?
Scope is the accessibility of variables, functions, and objects in some particular part of your code during runtime. In other words, scope determines the visibility of va...
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Q62. Why fragments are better than container divs?
Below are the list of reasons to prefer fragments over container DOM elements, 1. Fragments are a bit faster and use less memory by not creating an extra DOM node. This o...
Q63. What is a service worker?
A Service worker is basically a script (JavaScript file) that runs in the background, separate from a web page and provides features that don't need a web page or user in...
Q64. What are portals in React?
A Portal is a React feature that enables rendering children into a DOM node that exists outside the parent component's DOM hierarchy, while still preserving the React com...
Q65. How do you manipulate DOM using a service worker?
Service worker can't access the DOM directly. But it can communicate with the pages it controls by responding to messages sent via the `postMessage` interface, and those ...
Q66. What are stateless components?
If the behaviour of a component is independent of its state then it can be a stateless component. You can use either a function or a class for creating stateless componen...
Q67. How do you reuse information across service worker restarts?
The problem with service worker is that it gets terminated when not in use, and restarted when it's next needed, so you cannot rely on global state within a service worke...
Q68. What are stateful components?
If the behaviour of a component is dependent on the _state_ of the component then it can be termed as stateful component. These _stateful components_ are either function ...
Q69. What is IndexedDB?
IndexedDB is a low-level API for client-side storage of larger amounts of structured data, including files/blobs. This API uses indexes to enable high-performance searche...
Q70. How to apply validation on props in React?
When the application is running in _development mode_, React will automatically check all props that we set on components to make sure they have _correct type_. If the ty...