var is a functional scoped variable and it’s re- declarable and re-assignable. if you assign a value without declaring the variable it should be var.
let is a block-scoped variable and it isn’t re- declarable but re-assignable. if you declare a variable with let in a block you can't access that variable outside the block.
const is also a block-scoped variable and it isn’t re- declarable and not re-assignable.
When we declare a variable and do not assign a value it is “undefined”. But when we declare a variable and want to keep blank but not “undefined” we use “null”.
I am learning ReactJS for 6 months and every day I have learned some new things and I try to write something about what I learned today. Today I’m trying to talk about 10 basic things that every React developer needs to know.
There is some difference between Framework and Library. React is a library, not a framework. You can make the whole website front-end and back-end and can work with databases also with the framework. but the library focuses only on one thing and React mainly focus only building a user interface.
Block of code to try
Block of code to handle errors
Spread Operator is takes in an iterable (array) and expands it to a list of arguments. The … spread operator is useful for many different tasks
This is always returns the number of elements in the array.
const peoples = [“John”, “Kerry”, “Ana”];
peoples.length(); // Returns 3
Add a new items to the end of the array and returns index of new item.