I think var should be used sparingly. Because of hoisting, you can be left in a state where you've accidentally put a value into a variable before you initialise it. Also var allows you to declare your variable multiple times, so perhaps, if you're forgetful like me, you'll accidentally use the same variable name for different things and end up confused as to why the variable has the wrong value.
Using let prevents all that.
I'm a firm believer in the practice of declaring variables as close as possible to where you will start using them. let allows that, var secretly prevents it.
I also like to define the variables close to where they are being used. But I believe that if we declare the variables using var, we communicate that this variable is being used in the whole function body. I think it might be helpful to the code reader.
I can see how it could be useful to declare a var within an if, for example, if that's the first place it is used, as you can in python, but I think using var inside for, for example, opens you up to weird bugs.
I agree that in principle it is possible to use var responsibly. I still prefer let, as I know it'll be gone when my scope changes, so I don't have to think about it any more.
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I think
varshould be used sparingly. Because of hoisting, you can be left in a state where you've accidentally put a value into a variable before you initialise it. Alsovarallows you to declare your variable multiple times, so perhaps, if you're forgetful like me, you'll accidentally use the same variable name for different things and end up confused as to why the variable has the wrong value.Using
letprevents all that.I'm a firm believer in the practice of declaring variables as close as possible to where you will start using them.
letallows that,varsecretly prevents it.I also like to define the variables close to where they are being used. But I believe that if we declare the variables using
var, we communicate that this variable is being used in the whole function body. I think it might be helpful to the code reader.I can see how it could be useful to declare a
varwithin anif, for example, if that's the first place it is used, as you can in python, but I think usingvarinsidefor, for example, opens you up to weird bugs.I agree that in principle it is possible to use
varresponsibly. I still preferlet, as I know it'll be gone when my scope changes, so I don't have to think about it any more.