Q661. Is postMessages synchronous?
The postMessages are synchronous in IE8 browser but they are asynchronous in IE9 and all other modern browsers (i.e, IE9+, Firefox, Chrome, Safari).Due to this asynchrono...
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Q662. How do you prevent unnecessary Redux re-renders?
By default, `useSelector` re-renders a component whenever the **selected value's reference** changes between renders (it uses strict `===` comparison). Most unnecessary r...
Q663. What paradigm is Javascript?
JavaScript is a multi-paradigm language, supporting imperative/procedural programming, Object-Oriented Programming and functional programming. JavaScript supports Object-...
Q664. What is `createSelector`?
`createSelector` (from **Reselect**, which Redux Toolkit re-exports) creates **memoized selectors**. It takes one or more "input selectors" and a "result function", and o...
Q665. What is the difference between internal and external javascript?
**Internal JavaScript:** It is the source code within the script tag. **External JavaScript:** The source code is stored in an external file(stored with .js extension) an...
Q666. What is normalized Redux state?
**Normalized state** stores data the way a relational database would: each type of entity is kept in a lookup table keyed by ID, instead of being nested/duplicated inside...
Q667. Is JavaScript faster than server side script?
Yes, JavaScript is faster than server side scripts. Because JavaScript is a client-side script it does not require any web server’s help for its computation or calculatio...
Q668. Why is normalized state important for performance?
1. **O(1) lookups by ID** instead of scanning/`find()`-ing through an array every time a component needs one item. 2. **Updates are localized**: changing one entity only ...
Q669. How do you get the status of a checkbox?
You can apply the `checked` property on the selected checkbox in the DOM. If the value is `true` it means the checkbox is checked, otherwise it is unchecked. For example,...
Q670. What is Redux middleware?
**Middleware** provides a way to extend Redux with custom logic that runs **between dispatching an action and the moment it reaches the reducer**. It's the standard exten...