When it comes to learning JavaScript, many beginners get confused, especially those who are new to programming. Beginners usually think that they will master all topics of JavaScript before moving on to frameworks like React, Angular, and Vue, but this is not the case. It would take years to learn everything about a programming language, and trying to do that will not help you; rather, it will only make your coding journey more difficult. To become a successful developer, your goal should be to master the fundamentals of the language or framework, and, most importantly, you must build a habit of learning so that you have the ability to learn new things whenever you need to for any software engineering projects. This guide will break down exactly how much JavaScript you need to know and what skills are essential before moving forward.

Step 1: Six Essential Fundamentals of JavaScript

  • Variable Declarations: Know when and how to use the terms “let” and “const” to declare variables. You should also know about “var.”
  • Conditional Statements: Learn how to write conditional statements. There are eight conditions (>, <, >=, <=, ==, !=, ===, !==), and you need to know which one is used for what purpose. You should also know about && and || and how to use them to achieve multiple conditions. Moreover, you must know about if, else if, and else. Try writing conditions using one if statement, multiple else if statements, and one else statement. Write a code snippet that finds a student’s grade from their mark number.
  • Arrays: Understand how to declare an array. You should also have a clear understanding of when and how terms like length, index, push, pop, indexOf, and includes work in JS. You should be comfortable working with arrays. For example, you should be able to check whether an element is present in an array or not. Take a look at how slice and splice work. For additional learning, you can explore shift, unshift, join, and, if you want to learn a bit more, check out Reduce.
  • Loops: You must know about two basic loops: the for loop and the while loop. You should also understand when to use “for of” and “for in”. We use “for of” and “for in” to iterate over array and object elements, respectively.
  • Functions: Functions are one of the most important concepts in programming. You should be able to declare a simple function and have a good understanding of when to return from a function and when not to. Aside from declaring a function, you should also be able to pass parameters into a function and call it.
  • Objects: Learn how to declare an object and access its properties. You should also learn how to use an array or another object as an object’s property value.

Step 2: Basic Data Types

  • Strings: What is a String? How do you declare a string? How do you find a specific character in a string? Followed by a string, you need to know about length, includes indexOf, toUpperCase, toLowerCase, subString, concat, which are built-in functions of JavaScript. For interview questions, find out whether a string is mutable or immutable.
  • Numbers: You have to know about numbers. What are integers and floats? How do you convert strings into numbers? You also need to know how to check whether a number is an integer or not. Find out more about NaN.
  • Boolean Values: Understand the usage of True and False in code. You also have to know about truthy and falsy values in JS.
  • Null and Undefined: What are Null and Undefined? What are the differences? You need to know when and how to check this.

Step 3: Explore JavaScript ES6

  • Template Literals: Knowledge of declaring a string variable using a template string and how to add a dynamic value from an object to that string. Moreover, you should know how to access values from a nested object or from an array that is inside an array.
  • Spread Operator: Learn how the Spread Operator (…) works. Learn how to copy an array and make a new array including new values. You should also know how to filter an array in JS using the filter function.
  • Arrow Functions: One of the most essential subjects to learn about is arrow functions. Try doing the following with arrow functions to level up your function skills:
    • Create an arrow function that doesn’t take parameters and returns a value.
    • Create an arrow function that takes one parameter and returns it after doubling it.
    • Create an arrow function that takes more than one parameter and performs some arithmetic operations using those, then returns the result.
  • Destructuring: Learn how to destructure simple object property values. Moreover, learn how to destructure complex objects like an array inside an object because in large-scale projects, you will be working with an API having a complex dataset.
  • Shorthand Object Declaration: Know how to declare an object using shorthand.
  • Default Parameters: Understand default parameters in functions.
  • Optional Chaining: Learn what optional chaining is and when and how to use it.

Step 4: Learn JavaScript Libraries

  • Look up min, max, ceil, floor, abs, round, and random in the Math library so you can determine if you need to use them at work in the future.
  • How do you declare a Date? How do you get the time from the date and format it?
  • Understand the use of Regular Expressions in JS.
  • Learn how to parse and stringify JSON values.

Step 5: Four Topics of the Browser API

  • Knowledge of Local and Session Storage. How to use them?
  • How do you use the Location API in the browser?
  • How do you use the History API in the browser?
  • Try fetching data from the jsonplaceholder website and printing data in the browser console.

Step 6: Advanced JS Techniques

  • Create a number array and then use “map” to double each value and store it in a new array. All of this should be done in a single line. Learn about the functions of map, forEach, filter, and find in JS. These four principles are among the most significant in JS.
  • Explore ternary operators and learn how they shortcut if-else statements.
  • Know about Logical AND(&&) and OR(||) operator.
  • Learn what ++, — ,+=, -= does. Moreover, try to know what active=!active means.
  • Understand Object.keys and Object.values.

Step 7: It’s a Must to Know About DEV Tools & Debugging

  • Console Tab
  • Source Tab
  • Application Tab
  • Network Tab
  • Elements Tab

Step 8: Basic Problem Solving with JavaScript

  • Play around with the DOM, DOM manipulation, and learn how to add event handlers to the DOM. Learn how to take data from input and display it in the UI. Try to do 3 or 4 projects using DOM manipulation concepts.
  • Know some theoretical concepts of JS, like how JavaScript works, the event loop, closure, etc. These concepts are not a must for doing projects, but they will help you understand how JS works. Moreover, they will also help you ace interviews.

This is a beginners’ guide just to get you started with JS, but most importantly, as a programmer, you will encounter more concepts related to JS when you start working with it professionally. You have to build a habit and keep in mind that, as a programmer, you will always need to learn new topics if your project or workplace demands it.

When it comes to programming, there’s nothing to be afraid of. You will ultimately cover all of the topics discussed in this article if you set a goal for the next three months and spend 6 to 8 hours each day on programming. If you stay consistent and focused, you will eventually cover all of the topics mentioned in this article.

Happy Coding! 👨‍💻

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