migrate to typescript

src/utils/createMemoryCache.ts

@@ -0,0 +1,43 @@
+export function createMemoryCache(memoryFn: (...args: any[]) => void, cacheTimeMs: number) {
+    if (isNaN(cacheTimeMs)) cacheTimeMs = 0;
+
+    // holds the promise results
+    const cache = new Map();
+    // holds the promises that are not fulfilled
+    const promiseMemory = new Map();
+    return (...args: any[]) => {
+        // create cacheKey by joining arguments as string
+        const cacheKey = args.join('.');
+        // check if promising is already running
+        if (promiseMemory.has(cacheKey)) {
+            return promiseMemory.get(cacheKey);
+        } else {
+            // check if result is in cache
+            if (cache.has(cacheKey)) {
+                const cacheItem = cache.get(cacheKey);
+                const now = Date.now();
+                // check if cache is valid
+                if (!(cacheItem.cacheTime + cacheTimeMs < now)) {
+                    return Promise.resolve(cacheItem.result);
+                }
+            }
+            // create new promise
+            const promise = new Promise(async (resolve) => {
+                resolve((await memoryFn(...args)));
+            });
+            // store promise reference until fulfilled
+            promiseMemory.set(cacheKey, promise);
+            return promise.then(result => {
+                // store promise result in cache
+                cache.set(cacheKey, {
+                    result,
+                    cacheTime: Date.now(),
+                });
+                // remove fulfilled promise from memory
+                promiseMemory.delete(cacheKey);
+                // return promise result
+                return result;
+            });
+        }
+    };
+}