In Mongoose, how can you ensure data integrity and validate schema definitions for embedded documents?
- Using the required property in the schema
- Using the validate method in the schema
- Using the embedded keyword in the schema
- Using the unique property in the schema
In Mongoose, you can ensure data integrity and validate schema definitions for embedded documents by using the validate method in the schema. This method allows you to define custom validation logic. The required property specifies that a field is required but doesn't validate the schema. The embedded and unique options are not standard Mongoose properties.
Which method would you use to concatenate multiple buffers in Node.js?
- buffer.concat()
- buffer.join()
- buffer.append()
- buffer.merge()
To concatenate multiple buffers in Node.js, you should use the buffer.concat() method. The other options are not valid methods for buffer concatenation.
What is the primary role of a template engine in web development?
- Parsing JSON data
- Creating API endpoints
- Generating dynamic content
- Executing server-side logic
The primary role of a template engine in web development is to generate dynamic content by combining templates (HTML) with data. Template engines allow developers to insert data into templates, making it easier to create dynamic web pages. Parsing JSON data, creating API endpoints, and executing server-side logic are tasks typically performed by other parts of a web application, not the template engine.
Which of the following template engines uses a tag-based syntax to embed JavaScript code into HTML?
- Handlebars
- EJS (Embedded JavaScript)
- Pug
- Mustache
EJS (Embedded JavaScript) is a template engine that uses a tag-based syntax to embed JavaScript code into HTML. This allows developers to include dynamic content and logic directly within HTML templates using <% %> tags. Handlebars, Pug, and Mustache have their own syntax and do not use this tag-based approach.
When writing unit tests, why is it advised to mock external dependencies?
- Mocking external dependencies ensures that unit tests run faster.
- Mocking external dependencies helps isolate the code being tested and ensures tests focus only on the specific unit.
- Mocking external dependencies allows unit tests to access real data from external services.
- Mocking external dependencies is not advisable in unit testing.
It's advised to mock external dependencies in unit testing to isolate the unit being tested and not rely on the behavior of external services or dependencies. This ensures that unit tests are reliable and that any failures are indicative of issues within the unit itself.
In the fs module's callback functions, the error is handled by the first parameter, usually represented by the variable __________.
- error
- err
- e
- errorObj
In Node.js, the error in the fs module's callback functions is typically handled by the first parameter, which is conventionally represented by the variable err. Developers check this parameter to determine if an error occurred during a file system operation.
The require function in Node.js is used to ________ modules.
- import
- export
- load
- include
In Node.js, the require function is used to load modules. It allows you to include external JavaScript files and use their exported functionalities in your code. It is a fundamental part of Node.js for modular development.
What is the significance of the error event in readable streams in Node.js?
- It indicates the stream is finished.
- It signifies the end of the data stream.
- It is triggered when an error occurs during stream processing.
- It is emitted when a readable stream is pause
In Node.js, the error event in readable streams is crucial for handling errors that occur during stream processing. When an error occurs while reading or processing data in a readable stream, the error event is emitted, allowing developers to handle and respond to errors appropriately.
The ESLint rule, no-unused-vars, helps in identifying the variables that are declared but not ________ in the code.
- used
- initialized
- declared
- defined
The ESLint rule no-unused-vars helps in identifying variables that are declared but not used in the code. It checks for declared variables that are not referenced elsewhere in the code.
The OPTIONS HTTP method is used when the browser is making a ________ request to the server.
- Preflight CORS
- GET
- POST
- PUT
The OPTIONS HTTP method is used when the browser is making a preflight CORS request to the server. A preflight request is a CORS mechanism that checks if the actual request (e.g., a GET or POST) is safe to send to the server by first making an HTTP OPTIONS request to ensure the server allows the requested method and headers.