Angular Interview Questions and Answers: Review what you know, especially if you have an Angular interview coming up. Refresh your knowledge!.
You know as an IT professional how important it is to keep up with new technologies and improve your skills. Since Angular is a popular front-end framework, it’s important to fully grasp its main ideas and recommended methods. Getting ready for an Angular interview can help you not only get your dream job but also learn more about this popular framework. Refresh your knowledge using our Angular Interview Questions and Answers blog post!.
Angular interview questions and answers that cover a wide range of topics have been put together in this article. These questions and answers touch on Angular fundamentals, component interactions, dependency injection, and many more essential concepts. These questions are meant to help you get ready for any kind of interview, no matter how experienced you are as a developer or how new you are to the Angular framework.
You will get a better understanding of many parts of the Angular framework by going over and practicing these interview questions. These include testing and state management, as well as performance optimization and coding standards. This article is also a great resource for both interviewees and interviewers, making sure that the Angular skills are evaluated in a thorough and useful way.
Without further ado, let’s look at these Angular interview questions and answers to help you learn more about this powerful front-end framework. Happy learning and good luck in your next interview!.
Feeling nervous about your upcoming JavaScript interview? Don’t sweat it! With a solid understanding of the Bluebird Promise Library, you’ll be well-equipped to answer even the toughest questions. This comprehensive guide will equip you with the knowledge and confidence you need to impress your interviewer and land your dream job.
But first let’s address the elephant in the room What exactly is a Promise?
Think of a promise as a magic box that holds the key to future success or failure. It shows what will happen in the end of an asynchronous operation, like getting data from a server or finishing a complicated calculation. This box remains in one of three states:
- Pending: The operation is still in progress, and the box remains unopened.
- Fulfilled: The operation succeeded, and the box opens to reveal the valuable result.
- Rejected: The operation failed, and the box opens to reveal the reason for the failure.
Now, let’s dive into the world of Bluebird, the superhero of Promise libraries.
Bluebird goes beyond the basic functionalities of native JavaScript Promises, offering a treasure trove of features that make your life as a developer much easier. Let’s explore some of its superpowers:
1, Concurrency Control
Imagine you need to fetch data from multiple APIs simultaneously. Bluebird’s .each method lets you handle this like a boss. It processes each API call sequentially, ensuring that you don’t overwhelm the servers with too many requests at once.
getTwitterAccountIdsFromDb() .each(account => getAccountInfoFromApiFor(account));2. Transformation Power:
Bluebird’s . map method is like a magic wand that transforms your data with ease. It runs a function on each item in an array and returns a new array with the changed items. And guess what? You can even control the concurrency of this transformation!.
let accounts = getTwitterAccountIdsFromDb() .map(account => getAccountInfoFromApiFor(account), { concurrency: 1 });3. Delaying Gratification:
Sometimes, you need to introduce a delay between operations. Bluebird’s . delay method is your go-to tool for this. It stops your code from running for a certain amount of time, giving you control over how your asynchronous tasks run.
getTwitterAccountIdsFromDb() .each(account => { return transformAccount(account) .delay(1000 * 60); });4. Exception Handling Extraordinaire:
Bluebird’s .catch method takes exception handling to a whole new level It allows you to define specific catch statements for different types of exceptions, mirroring the elegance of JavaScript’s try and catch mechanism
doSomethingAndReturnAPromise() .then(() => a.b.c.d()) .catch(TypeError, e => { // Handle TypeError here }) .catch(ReferenceError, e => { // Handle ReferenceError here }) .catch(e => { // Handle any other error here });5 The Finally Clause
Native Promises lack a clean-up mechanism that always executes after an exception. Bluebird’s .finally method comes to the rescue, ensuring that your code always runs, regardless of whether the Promise was fulfilled or rejected.
this.loading = true;getSomeExternalAPIValue() .then(processValue) .then(notifyUser) .catch(displayError) .finally(() => (this.loading = false));6. Object Interception with Tap:
Bluebird’s .tap method allows you to intercept the Promise success chain without affecting the data flow. It’s like a secret agent that observes the data passing through the chain without altering it.
doSomething() .then(...) .tap(doSomethingElse) .then(...);7. Promisifying Everything:
Bluebird’s promisify method is a true game-changer. It transforms any function with a callback signature into a Promise, making it seamlessly compatible with the Promise-based world.
var readFile = Promise.promisify(require("fs").readFile);readFile("a_file") .then(parse) .then(output) .catch(displayError);8. Mastering the Promise Interview:
Now that you’re armed with the knowledge of Bluebird’s superpowers, let’s tackle some common Promise interview questions:
- What is a Promise?
- What are the different states of a Promise?
- What are the benefits of using Bluebird over native Promises?
- How can you handle concurrency with Bluebird?
- Explain the difference between
.thenand.catch. - How can you use Bluebird to delay the execution of code?
- What is the purpose of the
.finallymethod?
By confidently answering these questions and demonstrating your understanding of Bluebird’s features, you’ll leave your interviewer impressed and well on your way to landing your dream job.
Remember, with great power comes great responsibility. Use Bluebird wisely and conquer the world of asynchronous programming!
11 How do you ensure proper error handling and logging in Angular applications?
To ensure proper error handling and logging in Angular applications:
1. Use global error handlers to catch and log unhandled exceptions.
2. Implement HTTP interceptors to handle errors at the HTTP request/response level.
3. Employ centralized error logging services, such as Sentry or LogRocket, for better monitoring and debugging.
4. Utilize custom error classes to provide more context about the error’s origin and type.
10 Can you explain how to use the Angular CLI to run unit tests and end-to-end tests?
The Angular CLI provides built-in support for running both unit tests and end-to-end (E2E) tests in your application.
To run unit tests, use the following command: ng.test.
This command will build your app, start the Karma test runner, and run the unit tests that were set up in the spec. ts files. The test results will be displayed in the terminal.
To run end-to-end tests, use the following command: ng.e2e.
This command will build your app, start the development server, and run the Protractor test runner to run the E2E tests that were set up in the * e2e-spec. ts files. The test results will be displayed in the terminal.
BlueBird and Q promises
FAQ
What does promise() do?
What is a promise what did they replace and why do they represent an improvement on the previous way asynchronous functions were handled?
What are the promises and how do they work?
Is Bluebird a promise library?
Bluebird is a fully featured promise library with focus on innovative features and performance See the bluebird website for further documentation, references and instructions. See the API reference here. For bluebird 2.x documentation and files, see the 2.x tree. Please use native promises instead if at all possible.
Does Bluebird support JavaScript promises?
When using script tags the global variables Promise and P (alias for Promise) become available. Bluebird runs on a wide variety of browsers including older versions. We’d like to thank BrowserStack for giving us a free account which helps us test that. Bluebird is a fully featured JavaScript promises library with unmatched performance.
Does Bluebird support native promises?
Bluebird still includes a lot of features like cancellation, iteration methods and warnings that native promises don’t. If you are using Bluebird for performance rather than for those – please consider giving native promises a shot and running the benchmarks yourself. The github issue tracker is only for bug reports and feature requests.
Why does Bluebird use promises?
For reasons to use promises in general, see the Why Promises? article. Bluebird is built with the following design principles in mind: Pragmatic and not theoretical – Bluebird will always pick the pragmatic route vs the theoretically elegant one when there is a conflict.
