![What Is the Underscore "_" in Javascript? [Duplicate]](https://docuprint.cloud68.co/uploads/what-is-the-underscore-in-javascript-duplicate_1200.jpg)
I'm doing a redux tutorial, and I saw a call like this:
this._render();
and it's defined elsewhere as:
_render() {
....
}
What is the underscore "_"? Why is it used?
3 Answers
This is convention of private methods and variables. In JavaScript there is no real privacy of classes.
It means that you should not use these method (starting with "_") out of your object. Of course technically you can, but "_" means that you should not.
Underscore (_) is just a plain valid character for variable/function name, it does not bring any additional feature.
However, it is a good convention to use underscore to mark variable/function as private. You can check Underscore prefix for property and method names in JavaScript for some previous discussion.
The underscore is simply a valid character in an identifier, so the method's name is _render.
It's a common pattern in languages without access modifiers to use underscores to denote private methods. In a language such as C#, which does have access modifiers, I could define a method as:
private void Foo() {}
The method Foo can then only be called from within the class which defined it.
In JavaScript you can't do this, so it's a typical design pattern to prefix the method with _ to show that it should be treated as private.
this._foo();
You can still call this method, it's just not considered good practice to do it outside of the class definition.
