Underscore Prefix in JavaScript

This article helps you understand the JavaScript underscore prefix in variables.

the Underscore Prefix in JavaScript Variables

The underscore _ is simply an acceptable character for variable/function names; it has no additional functionality.

Underscore variable is the standard for private variables and methods. There is no true class privacy in JavaScript.

It signifies that these methods (beginning with _) should not be used outside your object. Technically, you can, but _ indicates that you shouldn’t.

For example, we can define a method’s name as _render because the underscore is a permitted identifier character.

The use of underscores to designate secret methods is a typical trend in languages without access modifiers. In a language with access modifiers, such as C#, we could define a method as:

private void Soo() {}

Soo can only be called from within the class that defined it. However, you can’t do this in JavaScript, so a typical design pattern is to prefix the method to indicate that it should be considered private.

this._Soo();

You can still call this function outside of the class declaration; however, doing so is not recommended.