An Idiom is a low-level pattern specific to a programming language. An idiom describes how to implement particular aspects of components or the relationships between them using the features of the given language.

A Design Pattern provides a scheme for refining the subsystems or components of a software system, or the relationships between them. It describes a commonly recurring structure of communicating components that solves a general design problem within a particular context.

Building blocks are what you use: patterns can tell you how you use them, when, why, and what trade-offs you have to make in doing so.

patterns are considered to be a way of putting building blocks into context

A "pattern" has been defined as: "an idea that has been useful in one practical context and will probably be useful in others"

search engines and social networks presence

the end user is using a slow internet connection, especially mobile connection,the end user is running an underpowered device, for example an older generation mobile device,

functional update form of setState. It lets us specify how the state needs to change without referencing the current state

typically you want to modify refs in event handlers and effects

only the assigned variable name addVariable can be used to refer & execute it.

addFunction overshadows the addVariable in call stack of debugging tools.

a DOM mutation that is visible to the user must fire synchronously before the next paint so that the user does not perceive a visual inconsistency. (The distinction is conceptually similar to passive versus active event listeners.) For these types of effects, React provides one additional Hook called useLayoutEffect

This makes it suitable for the many common side effects, like setting up subscriptions and event handlers, because most types of work shouldn’t block the browser from updating the screen.

Note that a HOC doesn’t modify the input component, nor does it use inheritance to copy its behavior. Rather, a HOC composes the original component by wrapping it in a container component. A HOC is a pure function with zero side-effects.

The baseline here is detecting technical issues (counting errors, service availability, etc) but it's also worth monitoring business issues (such as detecting a drop in orders).

The number of transactions the blockchain can process can never exceed that of a single node that is participating in the network.