からasync.memoize()
、この関数のコメントの後の最後のelseブロックは何をしますか?
https://github.com/caolan/async/blob/master/lib/async.js#L671
async.memoize = function (fn, hasher) {
var memo = {};
var queues = {};
hasher = hasher || function (x) {
return x;
};
var memoized = function () {
var args = Array.prototype.slice.call(arguments);
var callback = args.pop();
var key = hasher.apply(null, args);
if (key in memo) {
callback.apply(null, memo[key]);
}
else if (key in queues) {
queues[key].push(callback);
}
else {
// what does this else block do?
queues[key] = [callback];
fn.apply(null, args.concat([function () {
memo[key] = arguments;
var q = queues[key];
delete queues[key];
for (var i = 0, l = q.length; i < l; i++) {
q[i].apply(null, arguments);
}
}]));
}
};
memoized.unmemoized = fn;
return memoized;
};