Is there something like the swift optional chaining in javascript?

function optionalChaining(obj, chain) {
  return chain
    .split('.')
    .reduce(function(acc, val) {
        return acc ? acc[val] : undefined;
    }, obj);
}

var user = {
 address: {
  street: 'No.969 West WenYi Road',
},
 a: { b: { c: 2 } },
}

optionalChaining(user, 'address.street'); // 'No.969 West WenYi Road'
optionalChaining(user, 'a.b.c') // 2

The function can simulate optional chaining.

2020 Answer, It Exists!!!

You can now directly use ?. (Optional Chaining) inline to safely test for existence. All modern browsers support it.

If a property exists, ?. proceeds to the next check, or returns the valid value. Any failure will immediately short-circuit and return undefined.

const example = {a: ["first", {b:3}, false]}

example?.a  // ["first", {b:3}, false]
example?.b  // undefined

// Dynamic properties ?.[]
example?.a?.[0]     // "first"
example?.a?.[1]?.a  // undefined
example?.a?.[1]?.b  // 3

// Functions ?.()
null?.()                // undefined
validFunction?.()       // result
(() => {return 1})?.()  // 1

// DOM Access
domElement?.parentElement?.children?.[3]?.nextElementSibling

If you do not check a case, the left-side property must exist. If not, it will throw an exception.

example?.First         // undefined
example?.First.Second  // Uncaught TypeError: Cannot read property 'Second' of undefined

?. Browser Support - 82%, Oct 2020

Node Support - 14+

Mozilla Documentation

Optional chaining has now been added to the language using the same ?. syntax as Swift, so I recommend doing it that way unless you need to support older browser versions.

If you do, I've written a function that handles this:

function getSafe (func) {
    try {
        return func()
    } catch (e) {
        if (e instanceof TypeError) {
            return undefined
        } else {
            throw e
        }
    }
}

Call it like this:

if (getSafe(() => params.profile.address.default))

This works because by wrapping it in an anonymous function, it isn't evaluated until the try/catch block, which will then catch the error and return undefined if any of the parent properties are undefined.

Checking whether e is a TypeError prevents it from swallowing any other errors the function might throw so those can still be handled as needed. If you want it to just return undefined on any error, you can remove that part:

function getSafeNoErrors (func) {
    try {
        return func()
    } catch {
        return undefined
    }
}

There is no such operator in native JS.

However, there is a Babel plugin that will accomplish that, please check https://github.com/davidyaha/ecmascript-optionals-proposal

Also, please refer to Null-safe property access (and conditional assignment) in ES6/2015 for more references