Memoizes a String -> String or String -> Promise String function persistently. It uses window.localStorage on the browser and the filesystem (~/.nano-persistent-memoizer) on Node. <1K compressed.
var memo = require("nano-persistent-memoizer");
var twice = memo("twice").async(str => {
for (var i = 0; i < 10000000; ++i) {
Math.sin(i);
}
return Promise.resolve(str + str);
});
(async () => {
console.log(await twice("foo")); // slow
console.log(await twice("bar")); // slow
console.log(await twice("foo")); // instant (cached)
console.log(await twice("bar")); // instant (cached)
twice.clear(); // clears cache
})();