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Converting React ES6 class to functional component - what to use for private methods?

I'm converting a React ES6 class-style component to a functional component. The one thing I'm slightly unsure of is how best to convert private class methods. As far as I can tell, I should convert them to functions within the functional component's function, as they need to be there to access the component's state. However, that presumably means that on each re-render, the function is going to get recreated:

Before

class Game extends React.Component {

    handleClick(i) { if (this.state.foo) { ... } }

}

After

function Game {

    function handleClick(i) { if (foo) { ... } }

}

Is this a problem performance-wise, and if so, is there any way to improve it?

Also, most guides I've read recommend assigning arrow functions to variables instead of just declaring functions, eg.

function Game {

    const handleClick = (i) => { if (foo) { ... } }

}

Is this purely stylistic, or is there another reason to use assigned arrow functions over regular nested function definitions?

Via Active questions tagged javascript - Stack Overflow https://ift.tt/1DRY7Xq

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