What is the point of prefixing function names with '_' React/React-native ?

Question

So as per convention since JavaScript doesn't have access modifiers I have to prefix "private" function names with an underscore(_). But I am a little confused here, say I am writing a class in C++ or Java that has two functions one that performs internal calculations and the second that returns the result of that internal calculation.

So, I have these two functions

performInternalSecretCalculation();
getResult();

the performInternalSecretCalculation() is supposed to be private since I don't want other classes to worry about how the class handles calculation and hence I don't export this function. Whereas getResult() is something that will be used by other classes and hence I make it public and export this function.

But in case of React classes I am not exporting any functions all the functions defined inside a react class are used within it. So what is the differentiator? When should I prefix an underscore before a function's name?

Answer 1

It is just a naming convention, used by some developers for internal methods to separate them from the lifecycle methods of react.

Lifecycle methods

• constructor
• getChildContext
• componentWillMount
• componentDidMount
• componentWillReceiveProps
• shouldComponentUpdate
• componentWillUpdate
• componentDidUpdate
• componentWillUnmount

List is borrowed from the AirBnB Style Guide.

Airbnb React/JSX Style Guide

I prefer the Style Guide from AirBnB. They suggest not to use underscore prefix. I force instead a clean order for the methods.