Category: JavaScript Answers

Sometimes, we want to receive email in Node.js.

In this article, we’ll look at how to receive email in Node.js.

How to receive email in Node.js?

To receive email in Node.js, we can use the node-imap package.

To install it, we run

npm install imap

Then we use it by writing

const Imap = require("imap");
const { inspect } = require("util");

const imap = new Imap({
  user: "mygmailname@gmail.com",
  password: "mygmailpassword",
  host: "imap.gmail.com",
  port: 993,
  tls: true,
});

const openInbox = (cb) => {
  imap.openBox("INBOX", true, cb);
};

imap.once("ready", () => {
  openInbox(function (err, box) {
    if (err) throw err;
    const f = imap.seq.fetch("1:3", {
      bodies: "HEADER.FIELDS (FROM TO SUBJECT DATE)",
      struct: true,
    });
    f.on("message", (msg, seqno) => {
      console.log("Message #%d", seqno);
      const prefix = "(#" + seqno + ") ";
      msg.on("body", (stream, info) => {
        let buffer = "";
        stream.on("data", (chunk) => {
          buffer += chunk.toString("utf8");
        });
        stream.once("end", () => {
          console.log(
            prefix + "Parsed header: %s",
            inspect(Imap.parseHeader(buffer))
          );
        });
      });
      msg.once("attributes", (attrs) => {
        console.log(prefix + "Attributes: %s", inspect(attrs, false, 8));
      });
      msg.once("end", () => {
        console.log(prefix + "Finished");
      });
    });
    f.once("error", (err) => {
      console.log("Fetch error: " + err);
    });
    f.once("end", () => {
      console.log("Done fetching all messages!");
      imap.end();
    });
  });
});

imap.once("error", (err) => {
  console.log(err);
});

imap.once("end", () => {
  console.log("Connection ended");
});

imap.connect();

to receive email via IMAP.

We create an IMAP instance with the credentials for the email server.

Then we listen to the ready event with imap.onace.

In it, we call imap.seq.fetch to fetch the emails.

And then we call f.on with 'message' and the callback that gets the messages from a stream.

We received everything when the end event is received, which we listen to by calling msg.once with 'end' and the event handler callback.

And we call imap.connect() to make the connection to the IMAP server.

Conclusion

To receive email in Node.js, we can use the node-imap package.

To fix the ‘Error: Cannot GET /’ error message with Node.js and Express, we need to add the route handler for the GET / route.

For instance, we write

app.get("/", (req, res) => {
  res.render("index.html");
});

to call app.get with '/' and the route handler to handle GET requests to the / route.

In the route handler for the GET / route, we call res.render to render the index.html template on the screen.

Sometimes, we want to fix the "Unexpected token ‘import’" error while running Jest tests.

In this article, we’ll look at how to fix the "Unexpected token ‘import’" error while running Jest tests.

How to fix the "Unexpected token ‘import’" error while running Jest tests?

To fix the "Unexpected token ‘import’" error while running Jest tests, we should add the module that’s causing the error to the transformIgnorePatterns array.

For instance, we write

module.exports = {
  //...
  transformIgnorePatterns: ["/node_modules/(?!vue-awesome)"],
  //...
};

in jest.config.js to add the "/node_modules/(?!vue-awesome)" path to the transformIgnorePatterns array if the vue-awesome module is causing the "Unexpected token ‘import’" error.

This will make Jest ignore the module when it’s doing its transformations.

Conclusion

To fix the "Unexpected token ‘import’" error while running Jest tests, we should add the module that’s causing the error to the transformIgnorePatterns array.

Sometimes, we want to use array reduce with condition in JavaScript.

In this article, we’ll look at how to use array reduce with condition in JavaScript.

How to use array reduce with condition in JavaScript?

To use array reduce with condition in JavaScript, we can use the array filter method to return an array with the filtered entries before we call reduce.

For instance, we write

records
  .filter(({ gender }) => gender === "GIRLS")
  .reduce((sum, record) => sum + record.value);

to call filter to return the items with the gender property set to 'GIRLS‘.

Then we call reduce to sum up the value property of each entry.

Conclusion

To use array reduce with condition in JavaScript, we can use the array filter method to return an array with the filtered entries before we call reduce.