Compendium of Questions I have been asked during Interviews.

• What is a Promise?
• How do you use a Promise?
• What are some of the Promise libraries available?
• Are Promises blocking or non-blocking?
• What is a Promise Chain?
• What do Promises seek to solve?
• For a chained Promise, does the next Promise have to wait for the resolution of the current Promise to finish?
• What is Promise.all()? How does it work?
• What methods are using by Promises?
• What are alternatives to Promises?

• Is JavaScript dynamic or static?
• Does JavaScript have types?
• What are the types available in JavaScript?
• What are the raw or primitive types in JavaScript?
• What is the difference between a primitive type and a non-primitive type?

• What is an array?
• Are arrays mutable or immutable in JavaScript?
• How can you reserve the elements in an Array?
• What are some methods available to you to manipulate Arrays?
• What libraries out there are helpful with array manipulation?
• Explain the following: map, filter and reduce?
• Are arrays primitive JavaScript types?

• Explain the Object Oriented Programming/Design paradigm?
• What is inheritance?
• What is polymorphism?
• What is method overloading?
• What can you achieve method overloading in JavaScript?
• What type of inheritance is implemented in JavaScript?
• What is a prototype?
• How do you use a prototype?
• What is the difference between declaring properties and methods in the class than outside of the class through the prototype?
• Explain prototypical inheritance.
• Contrast inheritance between JavaScript and Java.
• How do you instantiate a class in JavaScript?
• Can you create private variables or methods in JavaScript? Explain.

• From what do all objects in JavaScript descend?
• Are null and undefined objects?

• What is a Closure?
• What is the usage of Closure?
• Why are Closures important in the JavaScript language?
• Give an example of usage of a Closure?
• What is an IIFE?
• What are the uses cases of an IIFE?
• How do you return data from an IIFE?
• Does JavaScript have namespaces?
• How can you create namespaces in JavaScript?
• Explain “this”.
• What are some challenges that you may face while trying to access “this” within nested functions? How do you overcome them?
• What is the global object?

• What is the difference between == and === ?
• Does JavaScript support unary operators? Give an example.

• What is ES5?
• What is ES6?
• What is ES?
• What is the difference between ES5 and ES6?
• How do you overcome browsers not supporting modern features of JavaScript?
• What is TypeScript?
• Is TypeScript the same as JavaScript? Are they backwards compatible?
• Who oversees the JavaScript language?
• Is JavaScript open source?

• What is Functional Programming?
• Does JavaScript support Functional Programming?
• What does it mean for a function to be called “first class citizen”?
• What is a pure function?
• What is immutability?
• Does JavaScript support immutability?
• What libraries are useful for Functional Programming design?

• Is JavaScript pass by value or pass by reference?
• What is pass by value and pass by reference? What is their difference?
• Does JavaScript check for the number of arguments passed to a function?
• How can you ensure you are getting the number of arguments desired?
• How can you implement default values for parameters in JavaScript?
• Can you return a function from a function?
• What is recursion?
• Is recursion bad for performance?
• What is function composition?

• What is the Event Loop?
• Walk me through the event loop.
• What is the stack?
• What is the heap?
• What is the event queue?
• What does the time represent in a setTimeout function?
• How does JavaScript keep control of asynchronous calls?
• What is hoisting?
• What is a web worker?
• What is a service worker?

• What are generators?
• How do you use generators?
• What is an iterable object?
• What is async?

• Reverse a string without using any of the built in methods.
• Extract the domain of an email address.
• Extract the numbers of a phone number.

• What is Angular?
• What is a directive?
• What is a controller?
• What is a service?
• What is a filter?
• What is a component?
• What is the difference between a component and a directive?
• What is scope?
• What is a view?
• Is Angular MVC? Explain.
• What is the Angular digest cycle?
• How do you trigger the digest cycle?
• What are watches?
• Compare and contrast apply and digest.
• Explain the lifecycle of a directive.
• How do JavaScript and Angular event loops integrate?
• What is two-way binding?
• What is one-way binding?
• What are events?

• What is a directive?
• What is compile?
• What is link?
• What is postlink?
• Why are directives the best place to perform DOM manipulation?
• Give examples of common native directives.
• How do you build a custom directive?
• What type of directives can be built?
• What is a decorator directive?
• When should you use a directive as an element and when as an attribute?
• Should two attribute directives have isolate scopes? Explain.
• How can you communicate across directives?
• Compare and contrast ng-show and ng-if.

• What is a controller?
• How can controllers communication among each other?
• What is broadcast?
• What is emit?
• When should you use broadcast or emit?
• Explain scope inheritance?
• Are controllers always necessary? How can you avoid using a controller and why?

• What is a service?
• How can services be used in Angular?
• What are the advantages of services?
• What are some native services?
• How do you create a custom services?
• What is the difference between provider, factory and service?
• What is value and what is constant?

• How can you improve performance in Angular?
• Why is ng-repeat a source of bottlenecks in Angular?
• What is the maximum numbers of watchers an application can have?
• What is the maximum number of times that angular will run through the watch list? What happens if that number is exceeded?

• What are style guides?
• Why are style guides useful?
• Are you familiar with the guidelines set by Todd Motto or John Papa?

• What is Node.js?
• What is the relationship between Node.js and C++?
• What is V8?

• What is callback hell?
• What is promise hell?
• What is error first?
• What is middleware? Give examples.
• What is a buffer?
• What is a stream?
• What are some common promises libraries for Node.js?
• Explain the Node.js event loop.
• What is shrinkwrap?
• What is NPM?
• What is Yarn?
• What is the difference between NPM and Yarn?
• Is Node.js single thread or multithread?
• Is Node.js non-blocking? What does that mean and how is that achieved?
• What is Express?
• What is Restify?

• What is unit testing?
• What is e2e testing?
• What is an integration test?
• What is a functional test?
• Why is testing important?
• what is TDD?
• What is BDD?
• How do you test JavaScript?
• How do you test Angular?
• How do you test Node?
• How do you test CSS?

• What is CSS?
• What is SASS?
• What is LESS?
• What is CSS3?
• What are the properties of the box component in CSS?
• What are CSS animations?
• What is a preprocessor?
• Why use SASS?
• How can you modify CSS properties dynamically?
• How do you overcome cross browser compatibility issues with CSS?
• Create a circle with CSS and place that circle on top of a box so that circle’s center aligns with the box top border.
• How do you stack elements with CSS?
• What is a flexbox?

• What is semantic HTML?
• Give examples of semantic HTML.
• Is a valid tag?

• What is SOLID?
• What is modularization?
• What is architecture in software terms?
• What are some different architectures?
• What is middleware?
• What is encapsulation?
• What are microservices?
• What is CI/CD?

• What is Version Control?
• What is git?
• What is git flow?
• What is a merge conflict?
• What is rebasing?
• What is a Pull Request?
• How do you perform a pull request?
• What is a fork?

• What is Gulp?
• Contrast Gulp with Grunt?
• What is a Gulp plugin?