You are developing a critical system where the cost of failure is very high. How would you design your testing strategy to ensure the reliability and stability of the system?
- Conduct extensive Unit Testing
- Rely on Beta Testing by end-users
- Implement Continuous Integration and Continuous Deployment (CI/CD) pipelines
- Perform thorough Regression Testing and use Automated Testing
To ensure the reliability and stability of a critical system, thorough Regression Testing and the use of Automated Testing are essential. These techniques help catch potential issues early and maintain system stability. Extensive Unit Testing alone may not cover all scenarios, and Beta Testing may be too risky for critical systems. CI/CD pipelines support automation but should be combined with robust testing.
You are optimizing the performance of a web application that uses EJS for rendering views. The views have a lot of dynamic content and are currently slow to render. How would you approach optimizing the rendering performance of the EJS templates?
- Implement caching mechanisms for frequently accessed templates using a caching library like Redis.
- Minimize the use of JavaScript in templates and offload complex logic to the server-side to reduce client-side rendering time.
- Precompile EJS templates into JavaScript functions to reduce runtime rendering overhead.
- Increase the client-side rendering capabilities by using a JavaScript framework like React or Angular.
To optimize the rendering performance of EJS templates, one effective approach is to precompile EJS templates into JavaScript functions. This reduces the runtime rendering overhead and improves the efficiency of rendering dynamic content.
In Pug, to extend a layout, you use the extends keyword and to fill a block within the layout, you use the ______ keyword.
- include
- fill
- block
- insert
In Pug, the extends keyword is used to extend a layout, and the block keyword is used to fill a block within the layout. This allows you to create modular and reusable templates. The other options do not serve the same purpose in Pug.
How does JavaScript's dynamic typing affect variable assignments and operations?
- It enforces strict type checking.
- It allows variables to change type during runtime.
- It requires explicit type annotations for all variables.
- It prevents type errors at compile time.
JavaScript's dynamic typing allows variables to change their data type during runtime. Unlike languages with static typing, you don't need to specify the data type of a variable explicitly.
Which of the following ESLint rules enforces consistent indentation in your code?
- no-console
- indent
- semi
- no-unused-vars
The indent rule in ESLint enforces consistent indentation in your code. It helps ensure that your code is properly formatted and readable by specifying the expected indentation style. The other options are for different rules, such as preventing the use of console, enforcing semicolons, or catching unused variables.
What is the first argument typically passed to a callback function in Node.js to handle errors?
- result
- data
- error
- callback
The first argument typically passed to a callback function in Node.js to handle errors is error. This argument holds information about any errors that may have occurred during the asynchronous operation. The other options (result, data, and callback) are used for different purposes in callback functions.
When the Event Loop encounters an asynchronous task, it offloads it to the ________ and continues to execute subsequent tasks.
- Callback Queue
- Worker Thread
- Event Emitter
- Main Memory
When the Event Loop encounters an asynchronous task, it offloads it to the Callback Queue and continues to execute subsequent tasks. These tasks are then processed from the Callback Queue when the main thread is available.
What is the significance of the call(), apply(), and bind() methods in JavaScript functions?
- They are used for declaring global variables.
- They enable asynchronous execution of functions.
- They manipulate the DOM.
- They facilitate the manipulation of function context and parameter passing.
call(), apply(), and bind() are methods in JavaScript used to manipulate the context in which a function is executed and to pass arguments to functions. They are commonly used in scenarios like setting the value of 'this' in a function and passing arguments dynamically. None of the other options correctly describe their purpose.
You are developing a real-time analytics dashboard that requires aggregation of data from multiple tables. How can you optimize the queries to ensure minimum latency in displaying the results?
- Use caching mechanisms
- Opt for synchronous queries to ensure real-time data
- Optimize database indexes
- Use a single table to store all data
To ensure minimum latency in a real-time analytics dashboard, using caching mechanisms is essential. Caching can store frequently used aggregated data and serve it quickly, reducing the need for complex queries. Options B and D do not align with best practices for real-time analytics. Option C is a good practice but not as directly related to real-time performance as caching.
In Express.js, to catch errors from a promise within a route, the next function should be called with the ______ as an argument.
- error
- promise
- err
- next
In Express.js, to catch errors from a promise within a route, the next function should be called with the err as an argument. This allows Express.js to recognize it as an error-handling middleware. Passing error, promise, or next itself would not trigger the error handling mechanism in Express.js.