Javascript covert Callback to Promise to Async/Await

We will start from working with callback to Promise then async/await in js.

Call Back

const fs = require("fs");

fs.readFile(".env", (err, data) => {
  console.log(err);
  console.log(data);
});

Promise

const fs = require("fs");
new Promise((resolve, reject) => {
  fs.readFile(".env", (err, data) => {
    if (err) return reject(err);
    return resolve(data);
  });
})
.then((data) => {
  console.log("data", data);
})
.catch((err) => {
  console.log("Err", err);
});

async/await

const fs = require("fs");

const getData = () => {
  return new Promise((resolve, reject) => {
    fs.readFile(".env", (err, data) => {
      if (err) return reject(err);
      return resolve(data);
    });
  });
};
(async () => {
  try {
    const data = await getData();
    console.log("getData", data);
} catch (e) {
  console.log("getData Err", e);
}
})();

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