Is there a null-coalescing (Elvis) operator or safe navigation operator in javascript?

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I'll explain by example:

Elvis Operator (?: )

The "Elvis operator" is a shortening of Java's ternary operator. One instance of where this is handy is for returning a 'sensible default' value if an expression resolves to false or null. A simple example might look like this:

def gender = user.male ? "male" : "female"  //traditional ternary operator usage

def displayName = user.name ?: "Anonymous"  //more compact Elvis operator

Safe Navigation Operator (?.)

The Safe Navigation operator is used to avoid a NullPointerException. Typically when you have a reference to an object you might need to verify that it is not null before accessing methods or properties of the object. To avoid this, the safe navigation operator will simply return null instead of throwing an exception, like so:

def user = User.find( "admin" )           //this might be null if 'admin' does not exist
def streetName = user?.address?.street    //streetName will be null if user or user.address is null - no NPE thrown

You can use the logical 'OR' operator in place of the Elvis operator:

For example displayname = user.name || "Anonymous" .

But Javascript currently doesn't have the other functionality. I'd recommend looking at CoffeeScript if you want an alternative syntax. It has some shorthand that is similar to what you are looking for.

For example The Existential Operator

zip = lottery.drawWinner?().address?.zipcode

Function shortcuts

()->  // equivalent to function(){}

Sexy function calling

func 'arg1','arg2' // equivalent to func('arg1','arg2')

There is also multiline comments and classes. Obviously you have to compile this to javascript or insert into the page as <script type='text/coffeescript>' but it adds a lot of functionality :) . Using <script type='text/coffeescript'> is really only intended for development and not production.

Elvis Operator (aka Safe Navigation) in JavaScript and TypeScript, One of the first feature requests of TypeScript was the Elvis operator. More precisely, the null-safe navigation operator. That's a variant of the  More precisely, the null-safe navigation operator. That's a variant of the "dot" operator allowing you to access attributes and methods even if the object preceding the dot is null or undefined. In most languages implementing the Elvis operator, the expression null?.firstName simply returns null , relieving the developers of guarding the attribute accesses with countless if statements.


I think the following is equivalent to the safe navigation operator, although a bit longer:

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

streetName will then be either the value of user.address.street or undefined.

If you want it to default to something else you can combine with the above shortcut or to give:

var streetName = (user && user.address && user.address.street) || "Unknown Street";

Optional chaining (?.), In object-oriented programming, the safe navigation operator is a binary operator that returns While the safe navigation operator and null coalescing operator are both null-aware C#[edit]. C# 6.0 and above have ?. , the null-conditional member access operator (which is also called the Elvis operator by JavaScript[​edit]. Null-safe property access (and conditional assignment) in ES6/2015. Is there a null-coalescing (Elvis) operator or safe navigation operator in javascript? 26.


Javascript's logical OR operator is short-circuiting and can replace your "Elvis" operator:

var displayName = user.name || "Anonymous";

However, to my knowledge there's no equivalent to your ?. operator.

Safe navigation operator, Jump to navigation Jump to search. Binary operator in computer programming. This article is about the use of a ?: operator as a binary operator. For use as a ternary operator, see ?:. In certain computer programming languages, the Elvis operator, often written ?: , or or || , is a In Kotlin, the Elvis operator returns its left​-hand side if it is not null, and its  No, there is no Elvis operator but you can use the || - var x = y || 10 for example or debug || console.log() – VLAZ Oct 17 '18 at 6:07


I've occasionally found the following idiom useful:

a?.b?.c

can be rewritten as:

((a||{}).b||{}).c

This takes advantage of the fact that getting unknown attributes on an object returns undefined, rather than throwing an exception as it does on null or undefined, so we replace null and undefined with an empty object before navigating.

Elvis operator, null coalescing operator javascript typescript safe navigation operator javascript optional chaining babel elvis operator typescript elvis operator javascript null  The Safe Navigation operator is used to avoid a NullPointerException. Typically when you have a reference to an object you might need to verify that it is not null before accessing methods or properties of the object. To avoid this, the safe navigation operator will simply return null instead of throwing an exception, like so:


i think lodash _.get() can help here, as in _.get(user, 'name'), and more complex tasks like _.get(o, 'a[0].b.c', 'default-value')

jquery, jquery - Is there a null-coalescing (Elvis) operator or safe navigation operator in javascript? I'll explain by example: Elvis Operator (?: ). The "Elvis operator" is a  In Kotlin, the Elvis operator returns its left-hand side if it is not null, and its right-hand side otherwise. A common pattern is to use it with return, like this: val foo = bar() ?: return; In Gosu, the ?: operator returns the right operand if the left is null as well.


Member access operators and expressions, Thread-safe delegate invocation. Use the ?. operator to check if a delegate is non​-null and invoke it in a thread-safe way (for example  In object-oriented programming, the safe navigation operator (also known as optional chaining operator, safe call operator, null-conditional operator) is a binary operator that returns null if its first argument is null; otherwise it performs a dereferencing operation as specified by the second argument (typically an object member access or an array index).


JS has no Elvis Operator, so how can I make this better?, And hope that proposal goes through. Once I learned the Elvis Operator existed in C#, every other null check solution seemed archaic :P Thank you :). There are a couple reasons to use the null coalescing operator: Converting Nullable properties to Non-Nullable properties and Ease of Reading. Converting to Non-Nullable Properties The Null Coalescing operator is useful for converting a nullable property into a non-nullable property.


Typescript null safe operator, Related Searches to javascript tutorial - “null coalescing” operator in JavaScript javascript The Safe Navigation Operator is also known as the "Elvis Operator". Don’t you have a feeling that sometimes C# code goes too much in null-checking? Yep, me too. But there are few C# 6 null-conditional operators that change it for good. Null-conditional / Elvis operator – ?. Let’s start with null-conditional operator – it’s ?.. It’s also called ‘elvis-operato