Allow exceptions to "jsx-no-lambda" rule

I think the usage of lambdas in ref attributes can warrant an exception from the “jsx-no-lambda” rules, since this is an easy way to get type-safe access to rendered elements.

The only alternative I see would be to create instance functions which would be cumbersome to write and still have to be bound using .bind(this).

So until we have a nicer way to generate these “bindings” for example using macros, it would be nice to allow lambdas on some attributes.

[adidahiya]

Doesn’t that result in the same issues as any other lambda in a JSX prop? Personally I like using a pattern like this for ref handlers:

class Button extends React.Component<{}, {}> {
    private buttonElement: HTMLElement;
    private refHandlers = {
        button: (ref) => this.buttonElement = ref,
        ...
    };

    public render() {
        return <button ref={this.refHandlers.button} />;
    }
}

@JKillian any thoughts on a whitelist of exceptions for this rule?

[jkillian]

A whitelist seems like unnecessary extra complexity to me. If a lamda is needed, it can be declared and initialized before the JSX code.

As far as the case of ref, there’s no need to recreate the lambda on every render, which is exactly what this rule is trying to prevent. Something like the code example above (the object literal isn’t necessary) works well.