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JavaScript from Beginner to Professional

You're reading from   JavaScript from Beginner to Professional Learn JavaScript quickly by building fun, interactive, and dynamic web apps, games, and pages

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Product type Paperback
Published in Dec 2021
Publisher Packt
ISBN-13 9781800562523
Length 546 pages
Edition 1st Edition
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Authors (4):
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Codestars By Rob Percival Codestars By Rob Percival
Author Profile Icon Codestars By Rob Percival
Codestars By Rob Percival
Laurence Svekis Laurence Svekis
Author Profile Icon Laurence Svekis
Laurence Svekis
Maaike van Putten Maaike van Putten
Author Profile Icon Maaike van Putten
Maaike van Putten
Rob Percival Rob Percival
Author Profile Icon Rob Percival
Rob Percival
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Toc

Table of Contents (19) Chapters Close

Preface 1. Getting Started with JavaScript FREE CHAPTER 2. JavaScript Essentials 3. JavaScript Multiple Values 4. Logic Statements 5. Loops 6. Functions 7. Classes 8. Built-In JavaScript Methods 9. The Document Object Model 10. Dynamic Element Manipulation Using the DOM 11. Interactive Content and Event Listeners 12. Intermediate JavaScript 13. Concurrency 14. HTML5, Canvas, and JavaScript 15. Next Steps 16. Other Books You May Enjoy
17. Index
Appendix – Practice Exercise, Project, and Self-Check Quiz Answers

Loops and objects

We have just seen how to loop over the values of an array, but we can also loop over the properties of an object. This can be helpful when we need to go over all the properties but don't know the exact properties of the object we are iterating over.

Looping over an object can be done in a few ways. We can use the for in loop to loop over the object directly, or we can convert the object to an array and loop over the array. We'll consider both in the following sections.

for in loop

Manipulating objects with loops can also be done with another variation of the for loop, the for in loop. The for in loop is somewhat similar to the for of loop. Again here, we need to specify a temporary name, also referred to as a key, to store each property name in. We can see it in action here:

let car = {
  model: "Golf",
  make: "Volkswagen",
  year: 1999,
  color: "black",
};
for (let prop in car){
  console.log(car[prop]);...
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