Gain insights into JavaScript fundamentals. Delve into variables, operators, functions, arrays, objects, and loops. Discover essential concepts to advance further in your coding journey with this beginner-friendly course.

This is an introduction to JavaScript for the complete beginner. It'll provide the fundamentals of the language. Topics include variables, operators, functions, arrays, objects, and loops. After this course, you should be ready to further your learning through advanced courses or other resources.

There is NO installation required for this course. Code can be viewed and run directly from the lessons.

This course has been created by Arnav Aggarwal, a full-stack engineer. Arnav has attended a coding boot camp and has taught at another one. He has extensive experience understanding how people learn to code. In under a month, Arnav's published articles on JavaScript concepts have received over 50,000 views and have been featured on Medium.com and code mentor.io due to their value.

After this course, check out the next one in the series.

Step Up Your JS: A Comprehensive Guide to Intermediate JavaScript

https://goo.gl/GjM8Mu

Introduction to JavaScript: First Steps

We've seen that for-loops are great for looping through arrays. There's another type of loop for objects, the for-in loop.

let jon = {
    firstName: 'Jon',
    lastName: 'Smith',
    age: 34,
    profession: 'Developer',
    married: true
};

for(let key in jon) {
    console.log(key, ':', jon[key]);
}

We start it out as a standard for-loop.

    for() {
    		// body
    }

In the parentheses, we declare a variable using `let key`. After we declare the variable, we write the `in` keyword followed by the name of the object we want to work with.

Inside the loop, our variable `key` will be equal to the keys of the object `jon`. It'll go through each key, running our loop repeatedly until every property has been processed.

Note that we have to use bracket notation here because `key` is a variable and not a string. If we were to write `jon.key`, the loop would print `undefined` over and over because it would be looking for a `key` property.

By using bracket notation, we can give it a variable instead.

The for-in loop is specifically designed to work with objects. Learn how to loop through an object's keys in order to process each of them.

Introduction

Variables

Operators & if-statements

Functions

Arrays

Objects

Loops

Conclusion

for-in loops