My only, yet essential use for comma is in a for loop:
for (var i = 0, n = a.length; i < n; i++) {
var e = a[i];
console.log(e);
}
I went here to look up whether this is OK in JavaScript.
Even seeing it work, a question remained whether n is local to the function.
This verifies, n is local:
a=[3,5,7,11];
(function l () { for (var i = 0, n = a.length; i < n; i++) {
var e = a[i];
console.log(e);
}}) ();
console.log(typeof n == "undefined" ?
"as expected, n was local" : "oops, n was global");
For a moment I wasn't sure, switching between languages.
0
Created by codelion on 2020-03-11 20:13:29 +0000 UTC
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