| 47 | * }); |
| 48 | */ |
| 49 | export default function memoize(fn, hasher) { |
| 50 | var memo = Object.create(null); |
| 51 | var queues = Object.create(null); |
| 52 | hasher = hasher || identity; |
| 53 | var _fn = wrapAsync(fn); |
| 54 | var memoized = initialParams(function memoized(args, callback) { |
| 55 | var key = hasher.apply(null, args); |
| 56 | if (has(memo, key)) { |
| 57 | setImmediate(function() { |
| 58 | callback.apply(null, memo[key]); |
| 59 | }); |
| 60 | } else if (has(queues, key)) { |
| 61 | queues[key].push(callback); |
| 62 | } else { |
| 63 | queues[key] = [callback]; |
| 64 | _fn.apply(null, args.concat(rest(function(args) { |
| 65 | memo[key] = args; |
| 66 | var q = queues[key]; |
| 67 | delete queues[key]; |
| 68 | for (var i = 0, l = q.length; i < l; i++) { |
| 69 | q[i].apply(null, args); |
| 70 | } |
| 71 | }))); |
| 72 | } |
| 73 | }); |
| 74 | memoized.memo = memo; |
| 75 | memoized.unmemoized = fn; |
| 76 | return memoized; |
| 77 | } |