// Cache implementation based on Erik Rasmussen's `lru-memoize`: // https://github.com/erikras/lru-memoize var NOT_FOUND = 'NOT_FOUND'; function createSingletonCache(equals) { var entry; return { get: function get(key) { if (entry && equals(entry.key, key)) { return entry.value; } return NOT_FOUND; }, put: function put(key, value) { entry = { key: key, value: value }; }, getEntries: function getEntries() { return entry ? [entry] : []; }, clear: function clear() { entry = undefined; } }; } function createLruCache(maxSize, equals) { var entries = []; function get(key) { var cacheIndex = entries.findIndex(function (entry) { return equals(key, entry.key); }); // We found a cached entry if (cacheIndex > -1) { var entry = entries[cacheIndex]; // Cached entry not at top of cache, move it to the top if (cacheIndex > 0) { entries.splice(cacheIndex, 1); entries.unshift(entry); } return entry.value; } // No entry found in cache, return sentinel return NOT_FOUND; } function put(key, value) { if (get(key) === NOT_FOUND) { // TODO Is unshift slow? entries.unshift({ key: key, value: value }); if (entries.length > maxSize) { entries.pop(); } } } function getEntries() { return entries; } function clear() { entries = []; } return { get: get, put: put, getEntries: getEntries, clear: clear }; } export var defaultEqualityCheck = function defaultEqualityCheck(a, b) { return a === b; }; export function createCacheKeyComparator(equalityCheck) { return function areArgumentsShallowlyEqual(prev, next) { if (prev === null || next === null || prev.length !== next.length) { return false; } // Do this in a for loop (and not a `forEach` or an `every`) so we can determine equality as fast as possible. var length = prev.length; for (var i = 0; i < length; i++) { if (!equalityCheck(prev[i], next[i])) { return false; } } return true; }; } // defaultMemoize now supports a configurable cache size with LRU behavior, // and optional comparison of the result value with existing values export function defaultMemoize(func, equalityCheckOrOptions) { var providedOptions = typeof equalityCheckOrOptions === 'object' ? equalityCheckOrOptions : { equalityCheck: equalityCheckOrOptions }; var _providedOptions$equa = providedOptions.equalityCheck, equalityCheck = _providedOptions$equa === void 0 ? defaultEqualityCheck : _providedOptions$equa, _providedOptions$maxS = providedOptions.maxSize, maxSize = _providedOptions$maxS === void 0 ? 1 : _providedOptions$maxS, resultEqualityCheck = providedOptions.resultEqualityCheck; var comparator = createCacheKeyComparator(equalityCheck); var cache = maxSize === 1 ? createSingletonCache(comparator) : createLruCache(maxSize, comparator); // we reference arguments instead of spreading them for performance reasons function memoized() { var value = cache.get(arguments); if (value === NOT_FOUND) { // @ts-ignore value = func.apply(null, arguments); if (resultEqualityCheck) { var entries = cache.getEntries(); var matchingEntry = entries.find(function (entry) { return resultEqualityCheck(entry.value, value); }); if (matchingEntry) { value = matchingEntry.value; } } cache.put(arguments, value); } return value; } memoized.clearCache = function () { return cache.clear(); }; return memoized; }