React, sometimes referred to as a frontend JavaScript framework, is a JavaScript library created by Facebook. React uses one more thing heavily i.e ES6. ECMAScript was created to standardize JavaScript, and ES6 is the 6th version of ECMAScript, it was published in 2015, and is also known as ECMAScript 2015.
Also for my clarity got in-depth with the ES6 variables which are:
1) let: block scope
2) var: function scope const: block scope and
3) const: block scope
Things I had never viewed yet are keyword const not defining a constant value. It defines a constant reference to a value. Because of this, you can NOT:
Reassign a constant value
Reassign a constant array
Reassign a constant object
But you can:
Change the elements of the constant array
Change the properties of constant object