Author: John Au-Yeung

Sometimes, we want to fix the ‘Error: failed to serialize user into session’ error with Passport.js.

In this article, we’ll look at how to fix the ‘Error: failed to serialize user into session’ error with Passport.js.

How to fix the ‘Error: failed to serialize user into session’ error with Passport.js?

To fix the ‘Error: failed to serialize user into session’ error with Passport.js, we use the serializeUser and deserializeUser methods.

For instance, we write

passport.serializeUser((user, done) => {
  done(null, user);
});

passport.deserializeUser((user, done) => {
  done(null, user);
});

to call serializeUser with a callback to serialize the user data.

The callback is run when the operation is done.

We call deserializeUser with a callback to serialize the user data.

The callback is run when the operation is done.

We call done to indicate the operation is done

Conclusion

To fix the ‘Error: failed to serialize user into session’ error with Passport.js, we use the serializeUser and deserializeUser methods.

Sometimes, we want to copy a folder recursively in Node.js.

In this article, we’ll look at how to copy a folder recursively in Node.js.

How to copy a folder recursively in Node.js?

To copy a folder recursively in Node.js, we can use the copySync method from the fs-extra module.

For instance, we write

const fse = require('fs-extra');

const srcDir = `path/to/file`;
const destDir = `path/to/destination/directory`;

fse.copySync(srcDir, destDir, {
  overwrite: true
}, (err) => {
  if (err) {
    console.error(err);
  } else {
    console.log("success!");
  }
});

to call copySync with the source srcDir path, the destination destDir path, and an object with overwrite set to true to overwrite any existing files with the same name, and a callback that runs when copySync is done.

If there’re any errors, err will be set.

Conclusion

To copy a folder recursively in Node.js, we can use the copySync method from the fs-extra module.

Sometimes, we want to make a remote REST call with Node.js.

In this article, we’ll look at how to make a remote REST call with Node.js.

How to make a remote REST call with Node.js?

To make a remote REST call with Node.js, we can use axios.

We install it by running

npm i axios

Then we use it by writing

const url = `https://example.com`;

const {
  data
} = await axios({
  method: 'get',
  url,
})

to call axios with the 'get' request method and the request url.

It returns a promise with the response data stored in data.

Conclusion

To make a remote REST call inside Node.js, we can use axios.

Sometimes, we want to create folder or use existing with Node.js.

In this article, we’ll look at how to create folder or use existing with Node.js.

How to create folder or use existing with Node.js?

To create folder or use existing with Node.js, we can use the recursive option with mkdirSync or mkdir.

For instance, we write

fs.mkdirSync(dirpath, {
  recursive: true
})

to create the folder at the path given by dirpath if it doesn’t exists by setting recursive to true with mkdirSync.

mkdirSync creates the folder synchronously.

We can create a folder asynchronously with mkdir by writing

await fs.promises.mkdir(dirpath, {
  recursive: true
})

Conclusion

To create folder or use existing with Node.js, we can use the recursive option with mkdirSync or mkdir.

Sometimes, we want to save a base64-encoded image to disk with Node.js.

In this article, we’ll look at how to save a base64-encoded image to disk with Node.js.

How to save a base64-encoded image to disk with Node.js?

To save a base64-encoded image to disk with Node.js, we can use the fs.writeFile method.

For instance, we write:

const base64Data = str.replace(/^data:image\/png;base64,/, "");

const fs = require("fs")

fs.writeFile("out.png", base64Data, 'base64', (err) => {
  console.log(err);
});

to remove the MIME type prefix from the base64 string with string replace.

Then we call fs.writeFile with the path to write the file to, the base64data string, the 'base64' encoding, and a callback that runs when writeFile is done.

If there’s an error, err will be set.

We need to pass in 'base64' to write the file as a base64 encoded file.

Conclusion

To save a base64-encoded image to disk with Node.js, we can use the fs.writeFile method.