An example of reselect usage is a selector that filters and sorts data from the Redux store. This selector can take other selectors as input and use them to filter and sort the data before returning it. For example, you could create a selector that filters a list of items by a certain category and then sorts the results by price. This selector would only recompute when the input selectors (category and items) have changed, which can help to improve performance.

In React, you can use the standard HTML "label" element to associate a label with an input field or other form element. To do this, you can use the "for" attribute on the label element, and set it to the "id" of the input field. In JSX, you can use the "htmlFor" attribute instead of "for", because "for" is a reserved keyword in JavaScript.

In React, you can use the style attribute to apply styles to a component. The style attribute takes an object that contains CSS properties and values, similar to inline styles in HTML.

In React, comments can be written using the {/* */} syntax. This syntax allows comments to be included directly in JSX code without causing syntax errors. Comments can be used to provide additional information or documentation about components, or to temporarily disable parts of the code for debugging purposes.

HOC factory implementations are higher-order components that return a function. This function can then be used to create a new higher-order component that has a specific set of props or behavior. This can be useful for creating reusable HOCs that can be customized for specific use cases. For example, you could create a withData HOC factory that takes a data source as an argument and returns a HOC that fetches and passes data to the wrapped component.

The contextType property is used to consume a context value in a class component in React. To use contextType, you assign the context object to the contextType property in the class definition. This allows the component to access the context value using the this.context property. ContextType can only be used with a single context object and can only be used in class components.

The default value in context is used to provide a fallback value when a context value is not available. When a component consumes a context value, it looks for the context value in its ancestors. If no ancestor provides a value, the default value is used instead. The default value is typically used as a fallback or to provide a default value for the context.

Error boundaries are a way to handle errors in React components. In React v16, error boundaries are special components that catch and handle errors that occur during rendering. This can help prevent the entire application from crashing due to an error in a single component.

In React, you can apply vendor prefixes to inline styles by using the "react-style-prefixer" library. This library automatically adds vendor prefixes to CSS properties based on the browser's user agent, and can be used with inline styles or CSS-in-JS solutions like styled-components or emotion.

The decision to use CSS in JS is largely dependent on the specific project requirements and the preferences of the development team. CSS in JS can offer certain benefits, such as better modularity and encapsulation of styles, but it may not be the best choice for every project.