CODEWITHSUNDEEP
reactjsreact-nativestate
sean2078
sean2078

Reputation: 5460

Is it acceptable in React Native to set a variable on this vs. calling this.setState()?

Understanding that this.setState() will trigger a re-render of a component, if I have a view and I do not need to trigger a re-render of say, for example a View, is it acceptable to set a variable on this? Is there any downside to doing so since I only need to reference that variable value within the scope of the View code?

For example:

this.adHeight = 100

Versus:

this.setState({ adHeight: 100 })

Upvotes: 0

Views: 311

Answers (1)

Ferran Negre
Ferran Negre

Reputation: 3801

You are not providing enough information to give you an exact answer so I will start guessing. If that addHeight variable is not affecting your component UI, why do you need it in your component? Is that variable a constant or it can change?

You could do:

const addHeight = 100;
// or
const addHeight = someConstantFile.addHeight;
// or
const addHeight = someFile.someFunction();

export default MyComponent extends React.Component {
  // use the addHeight somewhere
}

If that variable is not a constant, you could pass it as a prop too (but you are saying that it does not affect your render function so I am wondering what is the purpose of that variable). Maybe you could paste the whole component here.

But anyway, I would say yes, you can do what you are asking. I'd recommend you to use _ thought, for example: this._listener. Then you could for example access this._listener from your componentDidMount and from your componentWillUnmount (typical example). BUT if you find yourself accessing that variable from your render function, it would mean that this variable should actually be a prop or part of your component state.

Upvotes: 1

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