React is awesome for building modern web apps, but before you dive in, it's important to feel comfortable with JavaScript basics. React doesn't replace JavaScript—it builds on it. So the better your foundation, the easier it is to learn React.
Here are the key JavaScript concepts you should know first
1. Variables and Data Types
- Start with the basics: how to create and use variables.
- Use let and const instead of var
- Know when to use each
- Understand different types of data: strings, numbers, booleans, arrays, and objects
You’ll use these all the time in React components.
2. Functions (Especially Arrow Functions)
Functions are used everywhere in React.
- Learn how to create normal and arrow functions
- Understand how arrow functions handle this
- Use them for event handlers, rendering lists, and more
3. ES6+ Features
Modern React uses modern JavaScript, especially features from ES6 and newer. Get familiar with:
- Destructuring: const { name } = props
- Spread/rest operators: ...props
- Template literals: `Hello, ${name}`
- Import/export: import Something from './file'
These will show up in almost every React file you write.
4. Arrays and Array Methods
In React, you’ll often need to work with lists of items. Know how to use:
- .map(): to display lists
- .filter(): to remove items
- .forEach(): to loop through items
- .reduce(): to calculate totals or combine values
5. Objects and How to Use Them
Props, state, and most React data are objects. Learn how to:
- Access object properties
- Copy objects using the spread operator
- Update values without changing the original
6. The this Keyword
React's newer features (like Hooks) don’t use this much, but it’s still important if you run into class-based components. Learn how this works in different situations.
7. Callbacks and Functions Inside Functions
In React, you’ll often pass functions as props or use them inside other functions. This is called a callback. It’s common in things like event handling or custom logic in hooks.
8. Promises and async/await
React apps often deal with data from APIs. That means you’ll need to handle asynchronous code. Learn how to:
- Use promises: .then() and .catch()
- Write async functions and use await to wait for results
9. Closures and Scope
React components often use functions that "remember" values from their parent scope. This is called a closure, and it’s useful for things like setting state or using effects correctly.
10. Basic DOM Knowledge
You don’t need to manipulate the DOM manually in React, but it helps to understand:
- How elements are structured
- How events work (like clicks or input)
- How browsers render changes
This makes it easier to understand what React is doing in the background.
Final Thoughts
You don’t need to master every detail of JavaScript before learning React—but having a solid understanding of these concepts will make things a lot easier.
It’s like learning to drive: React is the car, but JavaScript is the road. Knowing how the road works makes you a better driver.
