idx

Hadn't seen this before, but I've been using a library from Facebook called idx: https://github.com/facebookincubator/idx Idx is a bit more verbose because you have to write an arrow function for each invocation, and it doesn't support default values.

Because they were using a demo function from a JS lib that attempts to match error messages: https://github.com/facebookincubator/idx >The idx runtime function exists for the purpose of illustrating the expected behavior and is not meant to be executed. The idx function requires the use of a Babel plugin that replaces it with an implementation that does not depend on details related to browser error messages. https://github.com/facebookincubator/idx/issues/55

Interesting project, but I'd stick with idx[0] since I have transpilation setup most of the time anyway. Also some of you could be interested in optional.js[1], it's Java's Optional for js, makes it arguably more pleasant to deal with null values, no help for chaining though! [0] https://github.com/facebookincubator/idx [1] https://github.com/JasonStorey/Optional.js

Wouldn't this swallow errors that you wouldn't want it to swallow? e.g. you try to access a property on a value that's null (which you think isn't null), and instead of getting an error, nothing happens. Idx[0] is a way better solution to dealing with the boilerplate of checking for null/undefined that has 0 runtime cost due to being compiled away by babel. It works with type systems, and you can even use it as a babel macro[1]. With it idx(props, _ => _.user.friends[0].friends) compiles to props.user == null ? props.user : props.user.friends == null ? props.user.friends : props.user.friends[0] == null ? props.user.friends[0] : props.user.friends[0].friends Optional chaining[2] would add this to JS at the language level by using ?. as the operator. [0]: https://github.com/facebookincubator/idx [1]: https://github.com