Declarations of var variables get hoisted – the variable name initialization gets hoisted to the top of the containing function (or, if no function, to the top of the outer block). So var withVar = (function() {throw ‘error!’})() is parsed by the interpreter as var withVar; withVar = (function() {throw ‘error!’})() The same is not … Read more
For PHP >= 7.0: As of PHP 7 you can use the null-coalesce operator: $user = $_GET[‘user’] ?? ‘guest’; Or in your usage: <?= $myVar ?? ” ?> For PHP >= 5.x: My recommendation would be to create a issetor function: function issetor(&$var, $default = null) { return isset($var) ? $var : $default; } This … Read more
Option Infer must be on in order for this to function properly. If so, then omitting the type in VB.NET (Visual Basic 9) will implicitly type the variable. This is not the same as “Option Strict Off” in previous versions of VB.NET, as the variable is strongly-typed; it’s just done so implicitly (like the C# … Read more
What ReSharper suggests is clearly overuse of the var keyword. You can use it where the type is obvious: var obj = new SomeObject(); If the type is not obvious, you should rather write it out: SomeObject obj = DB.SomeClass.GetObject(42);
Scoping rules The main difference is scoping rules. Variables declared by var keyword are scoped to the immediate function body (hence the function scope) while let variables are scoped to the immediate enclosing block denoted by { } (hence the block scope). function run() { var foo = “Foo”; let bar = “Bar”; console.log(foo, bar); … Read more
Try This… <html> <head> <script> function myFunction() { var number = “123”; document.getElementById(“myText”).innerHTML = number; } </script> </head> <body onload=”myFunction()”> <h1>”The value for number is: ” <span id=”myText”></span></h1> </body> </html>
With var you have a function scope, and only one shared binding for all of your loop iterations – i.e. the i in every setTimeout callback means the same variable that finally is equal to 6 after the loop iteration ends. With let you have a block scope and when used in the for loop … Read more
Yes, a Var in Clojure is similar to a C pointer. This is poorly documented. Suppose you create a function fred as follows: (defn fred [x] (+ x 1)) There are actually 3 things here. Firstly, fred is a symbol. There is a difference between a symbol fred (no quotes) and the keyword :fred (marked … Read more
In the PhpStorm IDE from JetBrains, you can use /** @var SomeObj[] */, e.g.: /** * @return SomeObj[] */ function getSomeObjects() {…} The phpdoc documentation recommends this method: specified containing a single type, the Type definition informs the reader of the type of each array element. Only one Type is then expected as element for … Read more
There’s no extra Intermediate language (IL) code for the var keyword: the resulting IL should be identical for non-anonymous types. If the compiler can’t create that IL because it can’t figure out what type you intended to use, you’ll get a compiler error. The only trick is that var will infer an exact type where … Read more