Variables in JavaScript

JS variables are used to store data values. But unlike any other language, the datatypes of that variable are not declared first like in C++. JavaScript has dynamic types. This means that the same variable can be used to hold different data types,

1. var, let, and const:

To declare variables we use var, let, and const.
var and let are very similar except in block scope which is discussed in the difference between var and let.
cont is the same as let but used only for constants.

1. Difference Between var and let: The main difference between var and let is that scope of var is global while that of let is limited to block. This means if I declare a variable using var, it can be excessed anywhere except in the case of a function, where you can't excess a variable outside the function. This can be a problem if we use it in loops for example.

1. Properties of const : People usually misunderstood the cont. It does not define a constant value. It defines a constant reference to a value, which means we can actually change the properties of a constant object or the element of a constant array. It is just you can reassign a value.

Comments

[Matt Ellen-Tsivintzeli]

The scope of var is not global if it's used within a function. var is scoped to the function it's declared in.