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Julio Santacruz
Julio Santacruz

Posted on • Updated on

Things all JavaScript beginners should know (Updated)

Hello

I'm currently looking for my first job as a frontend developer, I've been doing some technical interviews and they actually ask these questions (I took these questions from an instagram post). So I'll be looking for the answers and really understanding this topic.

Note. I already know some answers, but I will be updating this post from time to time. If you feel like collaborating with any answers, feel free to share in the comments.


1. What is the use of windows object?

The window object is a representation of the 'window' browser, the space were you navigate, it is created automatically by the browser, It is not a JavaScript Object...
The window object have a lot of his own properties and methods, y bet you know some of them...
| Properties | Methods |
| ----------- | ----------- |
| console | alert() |
| innerWidth | prompt() |
| InnerHeight | setTimeout()|
| scrollY | confirm() |


2. What are the different data types present in JavaScript?

Data types:

  • Boolean Type // true | false
  • Null Type // null
  • Undefined Type // undefined
  • Number Type // 123
  • BigIng Type // 123456789023456767766n
  • String Type // 'hello world'
  • Symbol Type
  • Object Type // {}

3. What is the difference between undefined value and null value?

Undefined is a vaiable that refers to something that doesn't exist

4. What is this [[[]]]?

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5. What are classes in ES^?

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6. What are the difference between cookie, local storage and session storage?

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7. What is the difference between setIntervals and setTimeout?

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8. What are arrow functions? How are they different from normal functions?

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9. What is this keyword?

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10. What are promises? How do you call a promise?

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11. What is the difference between observables & promises?

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12. What is callback hell?

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13. Explain closures

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14. What are pure functions?

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15. Difference between == and ===

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16. How to access DOM elements using js?

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17. What are higher order fuctions?

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18. Explain desctructing in Javascript

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19. What are spread and rest operators?

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20. What is even propagation event capturin, even bubbling?

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21. What is function currying?

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22. Difference between let and var

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23. Difference between call, apply and bind

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24. What is event loop ?

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25. What is weakMap and weakSet?

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26. What is the difference betwwin a function parameter and an argunment?

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27. What is function execution context & global execution context

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28. What is scope in JavaScript?

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29. How to create an array? List some of array methods

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30. What is hoisting?

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Top comments (0)

In defense of the modern web

I expect I'll annoy everyone with this post: the anti-JavaScript crusaders, justly aghast at how much of the stuff we slather onto modern websites; the people arguing the web is a broken platform for interactive applications anyway and we should start over;

React users; the old guard with their artisanal JS and hand authored HTML; and Tom MacWright, someone I've admired from afar since I first became aware of his work on Mapbox many years ago. But I guess that's the price of having opinions.