For me i find that readability is a good reason to declare functions as vars inside a function. It's much easier to follow (pseudo) code that says function hand

For me i find that readability is a good reason to declare functions as vars inside a function. It's much easier to follow (pseudo) code that says function handleCustomers = init some variables, var processCustomer = some function definition, forEach customer-->processCustomer(), do some update to some backend when we're done. It's even more pronounced when there are more blocks of code like processCustomer that are easier to read when pulled into their own function. It's especially useful in node when stringing a bunch of callbacks together.