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Why should you not use VAR in JavaScript?
Local variables are always faster than the variables in global scope. If you do not use var to declare a variable, the variable will be in global scope. For more information, you can search “scope chain JavaScript” in Google.
Why is var better C#?
var requires less typing. It also is shorter and easier to read, for instance, than Dictionary. var requires less code changes if the return type of a method call changes. You only have to change the method declaration, not every place it’s used.
Is it better to use var?
Overuse of var can make source code less readable for others. It is recommended to use var only when it is necessary, that is, when the variable will be used to store an anonymous type or a collection of anonymous types. The complaint that var reduces readability is not shared by everyone.
Do people still use VAR in JS?
var isn’t dead – it still does what it always has done — it’s function scoped and you can reassign or re-bind it. You may very well continue to choose it. There isn’t a right answer here, just opinions. Check them out and make your own decisions.
Is VAR faster C#?
So the answer is clearly no runtime performance hit! The C# compiler infers the true type of the var variable at compile time. There’s no difference in the generated IL. This doesn’t answer the question of whether var affects performance at all; you’re just stating your opinion on whether people should use it.
When to use VAR or not to’var’?
Use it whenever it is possible. It is not a variant type, it is a shortcut of the concrete type. It doesn’t hide type information, because the assignments and the variable name contains the needed information and Visual Studio helps you to know more about the variable if needed.
What does it mean to declare var type?
This doesn’t mean to declare a variant type. This means to tell the compiler to place Int32 where we wrote ‘var’. ‘var’ is simply syntactical sugar, but with many additional benefits. The other people who don’t like ‘var’ wanted to directly see the type of the variable.
When to use const instead of let / var?
It’s worth noting first that the vast majority of variables I declare are best suited for using const instead of let / var. This is because const will throw an error if an attempt is made to change its value after it has been declared, a useful feature to prevent accidental mutation.
When to use VAR instead of concrete type?
Personally since it is possible to use ‘var’ in C#, I always write ‘var’ whenever it is possible and every time I am refactoring a legacy application I remember the reasons why it is important to write ‘var’ instead of the concrete type.