A variable is an identifier for a value. We use variables to store values. A variable can be a username, an address and it should be meaningfull. We can say variables are containers that store values.
As a good rule of thumb, it is recommended you name your variables using the English Alphabet (A-Z), avoid the use of numbers, and use camelCasing for multiple word variables.
We can use either 'var' or 'let' to declare variables. 'var' is less recommended and it is better to use 'let' to declare variables.
for example:-
let username='John Doe';
Variables created with the keyword const are as the name shows , constant, meaning that they can not be overwritten. By using const , we can make sure that the value of the variable can not be chagned once we initialize it. If you don't what to re-assign a variable, const is the right choice.
const Rate=4.52;
We can not change the value of Rate to something other than 4.52.
Note: - Variable names have a strict set of rules. You must not pick a variable name that is a keyword or a reserved word.
Refer the list of words which cannot be used as variable names
Reserved Keywords in Javascript debugger default delete do else enum export extends false finally for function if implements import in Infinity instanceof interface let NaN new null package private protected public return static super switch this throw true try typeof undefined var void while with yield
