proxy-memoize
Version:
Intuitive magical memoization library with Proxy and WeakMap
121 lines (120 loc) • 4.44 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.memoize = void 0;
const proxy_compare_1 = require("proxy-compare");
// This is required only for performance.
// https://github.com/dai-shi/proxy-memoize/issues/68
const targetCache = new WeakMap();
// constants from proxy-compare
const HAS_KEY_PROPERTY = 'h';
const ALL_OWN_KEYS_PROPERTY = 'w';
const HAS_OWN_KEY_PROPERTY = 'o';
const KEYS_PROPERTY = 'k';
const trackMemoUntrackedObjSet = new WeakSet();
const isObject = (x) => typeof x === 'object' && x !== null;
const untrack = (x, seen) => {
if (!isObject(x))
return x;
const untrackedObj = (0, proxy_compare_1.getUntracked)(x);
if (untrackedObj) {
(0, proxy_compare_1.trackMemo)(x);
trackMemoUntrackedObjSet.add(untrackedObj);
return untrackedObj;
}
if (!seen.has(x)) {
seen.add(x);
Object.entries(x).forEach(([k, v]) => {
const vv = untrack(v, seen);
if (!Object.is(vv, v))
x[k] = vv;
});
}
return x;
};
const touchAffected = (dst, src, affected) => {
var _a, _b, _c;
if (!isObject(dst) || !isObject(src))
return;
const untrackedObj = (0, proxy_compare_1.getUntracked)(src);
const used = affected.get(untrackedObj || src);
if (!used) {
if (trackMemoUntrackedObjSet.has(untrackedObj)) {
(0, proxy_compare_1.trackMemo)(dst);
}
return;
}
(_a = used[HAS_KEY_PROPERTY]) === null || _a === void 0 ? void 0 : _a.forEach((key) => {
Reflect.has(dst, key);
});
if (used[ALL_OWN_KEYS_PROPERTY] === true) {
Reflect.ownKeys(dst);
}
(_b = used[HAS_OWN_KEY_PROPERTY]) === null || _b === void 0 ? void 0 : _b.forEach((key) => {
Reflect.getOwnPropertyDescriptor(dst, key);
});
(_c = used[KEYS_PROPERTY]) === null || _c === void 0 ? void 0 : _c.forEach((key) => {
touchAffected(dst[key], src[key], affected);
});
};
const isOriginalEqual = (x, y) => {
for (let xx = x; xx; x = xx, xx = (0, proxy_compare_1.getUntracked)(xx))
;
for (let yy = y; yy; y = yy, yy = (0, proxy_compare_1.getUntracked)(yy))
;
return Object.is(x, y);
};
// properties
const OBJ_PROPERTY = 'o';
const RESULT_PROPERTY = 'r';
const AFFECTED_PROPERTY = 'a';
/**
* Create a memoized function
*
* @example
* import { memoize } from 'proxy-memoize';
*
* const fn = memoize(obj => ({ sum: obj.a + obj.b, diff: obj.a - obj.b }));
*
* @param options
* @param options.size - (default: 1)
* @param options.noWeakMap - disable tier-1 cache (default: false)
*/
function memoize(fn, options) {
var _a;
let memoListHead = 0;
const size = (_a = options === null || options === void 0 ? void 0 : options.size) !== null && _a !== void 0 ? _a : 1;
const memoList = [];
const resultCache = (options === null || options === void 0 ? void 0 : options.noWeakMap) ? null : new WeakMap();
const memoizedFn = (obj) => {
const cache = resultCache === null || resultCache === void 0 ? void 0 : resultCache.get(obj);
if (cache) {
return cache;
}
for (let i = 0; i < size; i += 1) {
const memo = memoList[(memoListHead + i) % size];
if (!memo)
break;
const { [OBJ_PROPERTY]: memoObj, [AFFECTED_PROPERTY]: memoAffected, [RESULT_PROPERTY]: memoResult, } = memo;
if (!(0, proxy_compare_1.isChanged)(memoObj, obj, memoAffected, new WeakMap(), isOriginalEqual)) {
touchAffected(obj, memoObj, memoAffected);
resultCache === null || resultCache === void 0 ? void 0 : resultCache.set(obj, memoResult);
return memoResult;
}
}
const affected = new WeakMap();
const proxy = (0, proxy_compare_1.createProxy)(obj, affected, undefined, targetCache);
const result = untrack(fn(proxy), new WeakSet());
touchAffected(obj, obj, affected);
const entry = {
[OBJ_PROPERTY]: obj,
[RESULT_PROPERTY]: result,
[AFFECTED_PROPERTY]: affected,
};
memoListHead = (memoListHead - 1 + size) % size;
memoList[memoListHead] = entry;
resultCache === null || resultCache === void 0 ? void 0 : resultCache.set(obj, result);
return result;
};
return memoizedFn;
}
exports.memoize = memoize;