Conclusion. The JavaScript double question mark is also known as the nullish coalescing operator. It’s an operator that simply returns the right-side expression when the left side expression is either null or undefined .
Read moreWhat is the question mark in Dart?
Dart offers some handy operators for dealing with values that might be null. One is the ??= assignment operator, which assigns a value to a variable only if that variable is currently null: int a; // The initial value of a is null.
Read moreWhat does a question mark after a variable mean?
The question mark in JavaScript is commonly used as conditional operator — called ternary operator when used with a colon (:) and a question mark (?) — to assign a variable name conditionally .
Read moreWhat does two question marks together mean?
If double question marks are uses it is to emphasise something in return, usually from the shock of the previous thing said . For example, if I said: ‘My dog just died’ (sad, but used for example…) Someone may reply.
Read moreWhat does double question mark mean in laravel?
operator known as Null Coalescing Operator . It returns its first operand if it exists and is not NULL; otherwise, it returns its second operand. It evaluates from left to right.
Read moreHow do you use late keyword in darts?
Use the late keyword to initialize a variable when it is first read, rather than when it’s created . It’s common to use late in combination with final , to defer the creation of read-only variables to when they are first read.
Read moreHow do you check if a variable is null in darts?
Checking Nulls and Null-Aware Operators in Dart
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