r/learnjavascript • u/Emil0hman • Dec 17 '18

JavaScript Functions - 4 Ways

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u/noruthwhatsoever Dec 18 '18

I've never had a linter complain about number 3. I'll usually go for 4 but if I'm doing something like a console.log() for debugging or data tracking I'll use 3 no problem.

Also 3 and 4 are the only ways to implicitly bind a function expression in react without having to manually call this.function = this.function.bind(this)

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u/scweiss1 Dec 18 '18

When you say you’re using the arrow functions in react, are those inside the Class definition?

class SampleClass extends React.Component {
	constructor(props) {
		super(props)
		this.state={}
	}
	const square = (x) => {
		return x*x
	}
	render(){...}
}

Every time I’ve tried to use fat arrow functions like this, I get a syntax error. At least the first few times I looked at the error (briefly) it was about “experimental syntax” not being turned on — any idea what I’m missing?

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u/noruthwhatsoever Dec 19 '18

Babel. Babel is what you're missing.

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u/scweiss1 Dec 22 '18

Okay... but I’m using Babel with webpack to transpire my code. Is there a specific preset I need, looks like ‘stage-0’ perhaps? Or plugins like ‘transform-decorators-legacy’?