You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
101 lines
3.2 KiB
101 lines
3.2 KiB
'use strict';
|
|
|
|
Object.defineProperty(exports, "__esModule", {
|
|
value: true
|
|
});
|
|
exports.default = memoize;
|
|
|
|
var _identity = require('lodash/identity');
|
|
|
|
var _identity2 = _interopRequireDefault(_identity);
|
|
|
|
var _slice = require('./internal/slice');
|
|
|
|
var _slice2 = _interopRequireDefault(_slice);
|
|
|
|
var _setImmediate = require('./internal/setImmediate');
|
|
|
|
var _setImmediate2 = _interopRequireDefault(_setImmediate);
|
|
|
|
var _initialParams = require('./internal/initialParams');
|
|
|
|
var _initialParams2 = _interopRequireDefault(_initialParams);
|
|
|
|
var _wrapAsync = require('./internal/wrapAsync');
|
|
|
|
var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
|
|
|
|
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
|
|
|
|
function has(obj, key) {
|
|
return key in obj;
|
|
}
|
|
|
|
/**
|
|
* Caches the results of an async function. When creating a hash to store
|
|
* function results against, the callback is omitted from the hash and an
|
|
* optional hash function can be used.
|
|
*
|
|
* If no hash function is specified, the first argument is used as a hash key,
|
|
* which may work reasonably if it is a string or a data type that converts to a
|
|
* distinct string. Note that objects and arrays will not behave reasonably.
|
|
* Neither will cases where the other arguments are significant. In such cases,
|
|
* specify your own hash function.
|
|
*
|
|
* The cache of results is exposed as the `memo` property of the function
|
|
* returned by `memoize`.
|
|
*
|
|
* @name memoize
|
|
* @static
|
|
* @memberOf module:Utils
|
|
* @method
|
|
* @category Util
|
|
* @param {AsyncFunction} fn - The async function to proxy and cache results from.
|
|
* @param {Function} hasher - An optional function for generating a custom hash
|
|
* for storing results. It has all the arguments applied to it apart from the
|
|
* callback, and must be synchronous.
|
|
* @returns {AsyncFunction} a memoized version of `fn`
|
|
* @example
|
|
*
|
|
* var slow_fn = function(name, callback) {
|
|
* // do something
|
|
* callback(null, result);
|
|
* };
|
|
* var fn = async.memoize(slow_fn);
|
|
*
|
|
* // fn can now be used as if it were slow_fn
|
|
* fn('some name', function() {
|
|
* // callback
|
|
* });
|
|
*/
|
|
function memoize(fn, hasher) {
|
|
var memo = Object.create(null);
|
|
var queues = Object.create(null);
|
|
hasher = hasher || _identity2.default;
|
|
var _fn = (0, _wrapAsync2.default)(fn);
|
|
var memoized = (0, _initialParams2.default)(function memoized(args, callback) {
|
|
var key = hasher.apply(null, args);
|
|
if (has(memo, key)) {
|
|
(0, _setImmediate2.default)(function () {
|
|
callback.apply(null, memo[key]);
|
|
});
|
|
} else if (has(queues, key)) {
|
|
queues[key].push(callback);
|
|
} else {
|
|
queues[key] = [callback];
|
|
_fn.apply(null, args.concat(function () /*args*/{
|
|
var args = (0, _slice2.default)(arguments);
|
|
memo[key] = args;
|
|
var q = queues[key];
|
|
delete queues[key];
|
|
for (var i = 0, l = q.length; i < l; i++) {
|
|
q[i].apply(null, args);
|
|
}
|
|
}));
|
|
}
|
|
});
|
|
memoized.memo = memo;
|
|
memoized.unmemoized = fn;
|
|
return memoized;
|
|
}
|
|
module.exports = exports['default'];
|