DEV Community

Leslie Sarfo Gyamfi
Leslie Sarfo Gyamfi

Posted on • Edited on

JavaScript Essentials for React Developers

Basics

⇥ Variable Declaration
⇥ Variable Scope
⇥ Variable Hoisting
⇥ Functions
⇥ Arrow Functions
⇥ Callback Functions
⇥ Closure
⇥ Basic Operators
⇥ Array Literals
⇥ Object Literals
⇥ if, if...else
⇥ for, for...in, for...of, while, do...while

Array.prototype Methods

⇥ forEach()
⇥ map()
⇥ reduce()
⇥ flat()
⇥ flatMap()
⇥ find()
⇥ filter()
⇥ slice()
⇥ splice()
⇥ push()
⇥ pop()
⇥ shift()
⇥ unshift()
⇥ some()
⇥ every()

Array Destructuring

It's frequently used in hooks esp. useState()

Example:

⇥ const [fruits, setFruits] = useState([]);

Array Spread

There are so many use cases. One of the place where we frequently spread an array is adding/updating/removing an item from the state.

Example:
Add an item to the starting of Array

⇥ let newArray = [itemToAdd, ...oldArray]

Object Destructuring

⬒ Properties are passed as an object parameter to our function component.

⬓ We can destructure it and, specify only those properties that we are going to use.

Example:

function MyComponent({name, address}) {

}

Object Spread

We may spread an object to pass those to a child component.

Example:

function MyComponent({name, address, ...rest}) {
return
}

Template Literals

⇥ Untagged Template Literals
⇥ Tagged Template Literals
This one is used heavily in few styling libraries.

ES Modules

⇥ import
⇥ import {}
⇥ export
⇥ export default

Conclusion

⬖ Learning method varies from person to person.

⬘ Though it's not mandatory to have JS knowledge, you can learn both React and JS at the same time.

⬗ But for a smooth riding, it's advisable to have basic knowledge of JS before starting your React journey.

Top comments (3)

Collapse
 
curiousdev profile image
CuriousDev

I would say, you do not need React for these points. These are independent and I suggest learning without any UI Framework at the beginning.

Collapse
 
kwamedev profile image
Leslie Sarfo Gyamfi

Great suggestion.

Collapse
 
knowscount profile image
KnowsCount

great content!.. but one could hardly call himself a react dev if one doesn't know these I say.