ECMASCRIPT: Optional Chaining | Stage 3

Optional chaining is at stage 3 🎉🎉. This one is my favourite. Soon will be available in TypeScript.

tc39 / proposal-optional-chaining

Optional Chaining for JavaScript

Status

ECMAScript proposal at stage 4 of the process.

Authors

• Claude Pache (github)
• Gabriel Isenberg (github, twitter)
• Daniel Rosenwasser (github, twitter)
• Dustin Savery (github, twitter)

Overview and motivation

When looking for a property value that's deep in a tree-like structure, one often has to check whether intermediate nodes exist:

var street = user.address && user.address.street;

Also, many API return either an object or null/undefined, and one may want to extract a property from the result only when it is not null:

var fooInput = myForm.querySelector('input[name=foo]')
var fooValue = fooInput ? fooInput.value : undefined

The Optional Chaining Operator allows a developer to handle many of those cases without repeating themselves and/or assigning intermediate results in temporary variables:

var street = user.

…

View on GitHub

Comments

[Drew Town]

Definitely one of the things I miss most from c# when I am using JavaScript. I'm glad to see it is making it into the language.

[Anwar]

This is definitively one of my most awaited features! Tons of checks will blow away!!

[Stephen Chiang]

Finally, the Elvis operator is entering the building!

[Vikas Raj]

I was so jealous of our iOS developers when I first saw them using optional chaining in Swift. And finally we'll be blessed with this feature. 👏👏