In OAuth 2.0, the "Authorization" endpoint is used by the client to obtain authorization from the resource owner. This step is part of the OAuth 2.0 authorization code flow, where the client redirects the resource owner to the authorization server to grant access. The "Token" endpoint (Option 2) is used to exchange an authorization code for an access token. The "Redirect" endpoint (Option 3) typically refers to where the authorization server redirects the resource owner after granting or denying access. "Consent" (Option 4) is a user interaction step but not an OAuth endpoint.

The scripts section in the package.json file primarily contains custom command shortcuts. These shortcuts allow you to run commonly used commands for your project, such as starting the application, running tests, or building the project. They are defined as key-value pairs where the key is the name of the command, and the value is the command to execute.

End-to-end (E2E) testing examines the application's entire flow, including user interfaces and interactions. Integration testing, on the other hand, concentrates on testing how different components or modules work together within the application.

Using object mode in streams is appropriate when you want to work with complex JavaScript objects as chunks, rather than raw binary or text data. It allows you to pass objects between streams without serialization. The other options do not typically require object mode.

To optimize slow-performing queries on a large dataset, creating proper database indexes is crucial. Indexes can significantly speed up query performance by allowing the database to quickly locate relevant data. Options A and B might help with other aspects but do not directly address query performance. Increasing server RAM may not always resolve query performance issues related to large datasets.

Cache stampede in high-traffic applications can be mitigated by using cache warming techniques. Cache warming involves preloading the cache with frequently accessed data, reducing the likelihood of cache misses and stampedes during high traffic.

Closures can be used to create stateful functions. These functions can maintain their own state independently because they have access to the variables in their containing closure. This allows them to remember data across multiple function calls.

In the http module, the write method of the response object is used to write a chunk of the response body. This method is typically used in scenarios where you want to stream data to the client as it becomes available, such as when serving large files.

ESLint can be a valuable tool in library development. It helps identify and fix coding errors, enforces coding standards, and ensures best practices are followed, reducing the likelihood of issues arising after publication. Relying solely on user feedback or manual code inspection may lead to post-release issues.

To implement a custom writable stream in Node.js, you should extend the Writable class and implement its _write method. This method is responsible for processing and writing data to the stream. The other options are not used for creating custom writable streams.

In JavaScript, when destructuring an object, the three dots (...) are called the "Spread" operator. The spread operator is used to unpack elements from an array or properties from an object.

Node.js uses an event loop to queue I/O operations and execute them asynchronously in a single thread, preventing blocking and maximizing performance. The other options describe incorrect behaviors or consequences of the event loop mechanism.