mirror of https://github.com/jkjoy/sunpeiwen.git
33 lines
654 B
JavaScript
33 lines
654 B
JavaScript
|
/*
|
||
|
|
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 = undefined;
|
||
|
|
return () => {
|
||
|
|
if (cache) {
|
||
|
|
return /** @type {T} */ (result);
|
||
|
|
} else {
|
||
|
|
result = fn();
|
||
|
|
cache = true;
|
||
|
|
// Allow to clean up memory for fn
|
||
|
|
// and all dependent resources
|
||
|
|
fn = undefined;
|
||
|
|
return /** @type {T} */ (result);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
module.exports = memoize;
|