source: imaps-frontend/node_modules/webpack/lib/util/memoize.js

/*
        MIT License http://www.opensource.org/licenses/mit-license.php
*/

"use strict";

/** @template T @typedef {function(): T} FunctionReturning */

/**
 * @template T
 * @param {FunctionReturning<T>} fn memorized function
 * @returns {FunctionReturning<T>} new function
 */
const memoize = fn => {
        let cache = false;
        /** @type {T | undefined} */
        let result;
        return () => {
                if (cache) {
                        return /** @type {T} */ (result);
                }

                result = fn();
                cache = true;
                // Allow to clean up memory for fn
                // and all dependent resources
                /** @type {FunctionReturning<T> | undefined} */
                (fn) = undefined;
                return /** @type {T} */ (result);
        };
};

module.exports = memoize;