cachedApiCAll.js

//Problem Statement
//Implement a function in JavaScript that caches the API response for the given amount of time.
//If a new call is made between that time, the response from the cache will be returned,
//else a fresh API call will be made.

/**
 *
 * @param {*} expiryTime in ms
 */
function cachedApi(expiryTime) {
  let cache = {};
  return async function (path, config = {}) {
    const key = generatekey(path, config);

    let entry = cache[key];
    console.log(Date.now());
    console.log("expiry time:: ", entry?.expiryTime);
    if (!entry || Date.now() > entry.expiryTime) {
      console.log("making new api call");
      try {
        let response = await fetch(path, config);
        let result = response.json();
        cache[key] = { result, expiryTime: Date.now() + expiryTime };
      } catch (error) {
        console.error("An error occured while making the api call");
      }
    }
    // console.log("cache:: ", cache);
    return cache[key].result;
  };
}

/**
 * generate unique key for each api call
 * @param {*} path
 * @param {*} config
 * @returns
 */
function generatekey(path, config) {
  const key = Object.keys(config)
    .sort((a, b) => a.localeCompare(b))
    .map((k) => k + ":" + config[k].toString())
    .join("&");
  return path + key;
}

//usage
let call = cachedApi(3000);
call("https://jsonplaceholder.typicode.com/todos/1", {}).then((res) =>
  console.log(res)
);

setTimeout(() => {
  call("https://jsonplaceholder.typicode.com/todos/1", {}).then((res) =>
    console.log(res)
  );
}, 700);

setTimeout(() => {
  call("https://jsonplaceholder.typicode.com/todos/1", {}).then((res) =>
    console.log(res)
  );
}, 2000);

setTimeout(() => {
  call("https://jsonplaceholder.typicode.com/todos/1", {}).then((res) =>
    console.log(res)
  );
}, 5000);