basant307/AI_Governance_Project

1'use strict';2 3Object.defineProperty(exports, "__esModule", {4    value: true5});6exports.default = memoize;7 8var _setImmediate = require('./internal/setImmediate.js');9 10var _setImmediate2 = _interopRequireDefault(_setImmediate);11 12var _initialParams = require('./internal/initialParams.js');13 14var _initialParams2 = _interopRequireDefault(_initialParams);15 16var _wrapAsync = require('./internal/wrapAsync.js');17 18var _wrapAsync2 = _interopRequireDefault(_wrapAsync);19 20function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }21 22/**23 * Caches the results of an async function. When creating a hash to store24 * function results against, the callback is omitted from the hash and an25 * optional hash function can be used.26 *27 * **Note: if the async function errs, the result will not be cached and28 * subsequent calls will call the wrapped function.**29 *30 * If no hash function is specified, the first argument is used as a hash key,31 * which may work reasonably if it is a string or a data type that converts to a32 * distinct string. Note that objects and arrays will not behave reasonably.33 * Neither will cases where the other arguments are significant. In such cases,34 * specify your own hash function.35 *36 * The cache of results is exposed as the `memo` property of the function37 * returned by `memoize`.38 *39 * @name memoize40 * @static41 * @memberOf module:Utils42 * @method43 * @category Util44 * @param {AsyncFunction} fn - The async function to proxy and cache results from.45 * @param {Function} hasher - An optional function for generating a custom hash46 * for storing results. It has all the arguments applied to it apart from the47 * callback, and must be synchronous.48 * @returns {AsyncFunction} a memoized version of `fn`49 * @example50 *51 * var slow_fn = function(name, callback) {52 *     // do something53 *     callback(null, result);54 * };55 * var fn = async.memoize(slow_fn);56 *57 * // fn can now be used as if it were slow_fn58 * fn('some name', function() {59 *     // callback60 * });61 */62function memoize(fn, hasher = v => v) {63    var memo = Object.create(null);64    var queues = Object.create(null);65    var _fn = (0, _wrapAsync2.default)(fn);66    var memoized = (0, _initialParams2.default)((args, callback) => {67        var key = hasher(...args);68        if (key in memo) {69            (0, _setImmediate2.default)(() => callback(null, ...memo[key]));70        } else if (key in queues) {71            queues[key].push(callback);72        } else {73            queues[key] = [callback];74            _fn(...args, (err, ...resultArgs) => {75                // #1465 don't memoize if an error occurred76                if (!err) {77                    memo[key] = resultArgs;78                }79                var q = queues[key];80                delete queues[key];81                for (var i = 0, l = q.length; i < l; i++) {82                    q[i](err, ...resultArgs);83                }84            });85        }86    });87    memoized.memo = memo;88    memoized.unmemoized = fn;89    return memoized;90}91module.exports = exports.default;