"use strict";
exports.__esModule = true;
exports.default = useStableMemo;
var _react = require("react");
function isEqual(a, b) {
if (a.length !== b.length) return false;
for (let i = 0; i < a.length; i++) {
if (a[i] !== b[i]) {
return false;
}
}
return true;
}
/**
* Identical to `useMemo` _except_ that it provides a semantic guarantee that
* values will not be invalidated unless the dependencies change. This is unlike
* the built in `useMemo` which may discard memoized values for performance reasons.
*
* @param factory A function that returns a value to be memoized
* @param deps A dependency array
*/
function useStableMemo(factory, deps) {
let isValid = true;
const valueRef = (0, _react.useRef)();
// initial hook call
if (!valueRef.current) {
valueRef.current = {
deps,
result: factory()
};
// subsequent calls
} else {
isValid = !!(deps && valueRef.current.deps && isEqual(deps, valueRef.current.deps));
}
const cache = isValid ? valueRef.current : {
deps,
result: factory()
};
// must update immediately so any sync renders here don't cause an infinite loop
valueRef.current = cache;
return cache.result;
}