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import React from 'react';
const BEAT_LIMIT = 1000 * 60 * 10;
/**
* A helper class to map keys to values.
* It supports both primitive keys and object keys.
*/
class ArrayKeyMap<T> {
map = new Map<string, T>();
// Use WeakMap to avoid memory leak
objectIDMap = new WeakMap<object, number>();
nextID = 0;
lastAccessBeat = new Map<string, number>();
// We will clean up the cache when reach the limit
accessBeat = 0;
set(keys: React.DependencyList, value: any) {
// New set will trigger clear
this.clear();
// Set logic
const compositeKey = this.getCompositeKey(keys);
this.map.set(compositeKey, value);
this.lastAccessBeat.set(compositeKey, Date.now());
}
get(keys: React.DependencyList) {
const compositeKey = this.getCompositeKey(keys);
const cache = this.map.get(compositeKey);
this.lastAccessBeat.set(compositeKey, Date.now());
this.accessBeat += 1;
return cache;
}
getCompositeKey(keys: React.DependencyList) {
const ids = keys.map<string>((key) => {
if (key && typeof key === 'object') {
return `obj_${this.getObjectID(key)}`;
}
return `${typeof key}_${key}`;
});
return ids.join('|');
}
getObjectID(obj: object) {
if (this.objectIDMap.has(obj)) {
return this.objectIDMap.get(obj);
}
const id = this.nextID;
this.objectIDMap.set(obj, id);
this.nextID += 1;
return id;
}
clear() {
if (this.accessBeat > 10000) {
const now = Date.now();
this.lastAccessBeat.forEach((beat, key) => {
if (now - beat > BEAT_LIMIT) {
this.map.delete(key);
this.lastAccessBeat.delete(key);
}
});
this.accessBeat = 0;
}
}
}
const uniqueMap = new ArrayKeyMap();
/**
* Like `useMemo`, but this hook result will be shared across all instances.
*/
function useUniqueMemo<T>(memoFn: () => T, deps: React.DependencyList) {
return React.useMemo<T>(() => {
const cachedValue = uniqueMap.get(deps);
if (cachedValue) {
return cachedValue as T;
}
const newValue = memoFn();
uniqueMap.set(deps, newValue);
return newValue;
}, deps);
}
export default useUniqueMemo;
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