Why put $ in front of the variable?

Question

JavaScript

I dug into someone else's code and found that in classes, in the names of class properties, the developer writes some variables like this:
this.$variable
Why $?

Answer 1

This is how you mark variables that contain a jquery object.

Answer 2

There is such a practice - the buck is placed in front of those variables in which there should be objects.
Just to make it easy to visually distinguish them from other variables.
The language itself does not care, but the programmer sometimes needs to distinguish them.

Answer 3

It was originally the practice to refer to jQuery objects this way.
But I, for example, also designate ordinary DOM nodes in the same way.

Answer 4

This is a form of Hungarian notation. This is the symbol that precedes the name of a variable and is used solely to provide you with information about the variable.