for (var foo in bar) print(foo);
for (final foo in bar) print(foo);
Is there any difference in performance between these two? Or is the only difference "avoiding accidental reassignments"?
Edit:
prefer_final_locals mentions compiler performing optimizations when final is used. Will it apply here? dart2js output matches for the 2 snippets above. Not sure about dart2native.
The only difference is that you can reassign the foo value if you use var.
for (var foo in bar) {
foo = foo + 5;
print(foo);
}
doing so using final would not work
for (final foo in bar) {
foo = foo + 5; //Error: The variable foo can be set only once
print(foo);
}
From Dart Style Guide:
DON'T use final for local variables.
var is shorter, and final does not change the meaning of the code.
https://dart-lang.github.io/linter/lints/unnecessary_final.html