When your first argument is null, they’re basically the same except that the null coalescing won’t output an E_NOTICE when you have an undefined variable. The PHP 7.0 migration docs has this to say: The null coalescing operator (??) has been added as syntactic sugar for the common case of needing to use a ternary … Read more
Thanks to everyone who contributed to analyzing this issue. It is clearly a compiler bug. It appears to only happen when there is a lifted conversion involving two nullable types on the left-hand side of the coalescing operator. I have not yet identified where precisely things go wrong, but at some point during the “nullable … Read more
Update JavaScript now supports the nullish coalescing operator (??). It returns its right-hand-side operand when its left-hand-side operand is null or undefined, and otherwise returns its left-hand-side operand. Old Answer Please check compatibility before using it. The JavaScript equivalent of the C# null coalescing operator (??) is using a logical OR (||): var whatIWant = … Read more
It’s the null coalescing operator, and quite like the ternary (immediate-if) operator. See also ?? Operator – MSDN. FormsAuth = formsAuth ?? new FormsAuthenticationWrapper(); expands to: FormsAuth = formsAuth != null ? formsAuth : new FormsAuthenticationWrapper(); which further expands to: if(formsAuth != null) FormsAuth = formsAuth; else FormsAuth = new FormsAuthenticationWrapper(); In English, it means … Read more