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Node.JS Interview Questions and Answers


  1. What is an error-first callback?
    1. https://nodejs.org/api/errors.html#errors_error_first_callbacks
  2. How to print an error to console?
    1. console.error('There was an error', err);
  3. How to avoid a callback commotion?
    1. Use promises
  4. How to create a Promise?
    1. let promiseObject = new Promise((resolve, reject) => {});
  5. Difference between Promise and Callback?
    1. Callbacks handle success and failure, Promise has resolve and reject
    2. Callback can be called multiple times, Promise can be executed just once
  6. Why NodeJS?
    1. It is non-blocking / Asynchronous - Program goes on without being blocked with time consuming activity
    2. Node is single threaded
    3. Therefore Node is highly scalable
    4. Node should be used for data intensive, realtime applications and not for processing intensive applications
    5. It is built on top of Chrome V8 Engine
    6. Used by LinkedIn, Walmart, Paypal, Uber, Netflix
    7. Javascript in Frontend and Backend too
    8. Goes hand in hand with React and Angular
    9. Cross Platform - Can be installed on Windows/Linux/Mac
    10. Active Development Community
    11. It is a technology of choice. Not just a fad
    12. It is a bare bones framework
    13. Documentation is good
    14. Availability of good tutorials and solutions support is good.

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