Not null operator in javascript

There's a really good article about the difference in two terms here. Null: when a variable is null, it means it contains no data in it, but the variable is already defined in the code. Undefined: when a variable has not been defined before in the code, and as expected, it does not contain any value. Note that React's create-react-app tool-chain supports the null-coalescing since version 3.

From the release notes:. This said, in case you use create-react-app 3. It will hopefully be available soon in Javascript, as it is in proposal phase as of Apr, For people using Typescript, you can use the nullish coalescing operator from Typescript 3.

You can think of this feature - the?? When we write code like. None of the other answers compares all three of these. The nullish coalescing operator??

Now it has full support in latest version of major browsers like Chrome, Edge, Firefox , Safari etc. Here's the comparison between the null operator and Nullish Coalescing Operator. Babel 7. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Is there a "null coalescing" operator in JavaScript? Ask Question. Asked 12 years, 11 months ago. Active 15 days ago. Viewed k times. Is there a null coalescing operator in Javascript? Can I do better? Daniel Schaffer Daniel Schaffer There is now a Babel plugin which incorporates this exact syntax.

Note from now is stage 3 status! Note from January Nullish coalescing operator is available natively in Firefox 72 but optional chaining operator is still not. The nullish coalescing operator x?? Here's a good description about what that means: 2ality. Show 1 more comment. Active Oldest Votes. Update JavaScript now supports the nullish coalescing operator?? Old Answer Please check compatibility before using it.

Clarification Regardless of the type of the first operand, if casting it to a Boolean results in false , the assignment will use the second operand. Strings like "false", "undefined", "null", "0", "empty", "deleted" are all true since they are non-empty strings.

JustinJohnson makes a good point. This answer compares all three:?? Add a comment. Javascript doesn't have one. Most of the time peoples use the logical OR for this purpose but it doesn't work on property access.

And for the? Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow.

Learn more. Is it possible to check for null inline in javascript? Ask Question. Asked 3 years, 11 months ago. Active 14 days ago. Viewed 78k times. The getAddressComponent returns a null if it cannot find the key.

How can I simply check like this with? Improve this question. Pac0 Possible duplicate of JavaScript check if value is only undefined, null or false — Mackija. Is getAddressComponent async or not? Do you mean element! GalAbra No, I meant if I could somehow do something like this tc Show 1 more comment.

Active Oldest Votes. Improve this answer. You can also use the optional chaining operator when accessing properties with an expression using the bracket notation of the property accessor :. This example looks for the value of the name property for the member bar in a map when there is no such member.

The result is therefore undefined. When using optional chaining with expressions, if the left operand is null or undefined , the expression will not be evaluated. For instance:. The nullish coalescing operator may be used after optional chaining in order to build a default value when none was found:.

Change language. The Nullish Coalescing Operator. Logical nullish assignment?? Object initializer Operator precedence Optional chaining?.