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JavaScript Answers

How to use pipe() in Node.js net?

To use pipe() in Node.js net, we call the on method.

For instance, we write

const net = require("net");

net.createServer((socket) => {
  socket.write("Echo server\r\n");
  socket.on("data", (chunk) => {
    socket.write(chunk);
  });
  socket.on("end", socket.end);
});

to call createServer to create a server.

We call write to write a message.

And we call on to listen for data.

Categories
JavaScript Answers

How to display binary data as image in React?

To display binary data as image in React, we set the src prop to a base string.

For instance, we write

const data =
  "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";

const Example = ({ data }) => <img src={`data:image/jpeg;base64,${data}`} />;

ReactDOM.render(<Example data={data} />, document.getElementById("container"));

to set the src prop of the img element to a base64 string with the image content.

Categories
JavaScript Answers

How to fix Node npm install doesn’t create node_modules directory?

To fix Node npm install doesn’t create node_modules directory, we create a package.json file.

To do this, we run

npm init

to create a package.json file in the project folder.

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JavaScript Answers

How to fix Node.js https pem error: routines:PEM_read_bio:no start line?

To fix Node.js https pem error: routines:PEM_read_bio:no start line,. we read the SSL key and certificate file.

For instance, we write

const options = {
  key: fs.readFileSync("./key.pem", "utf8"),
  cert: fs.readFileSync("./server.crt", "utf8"),
};

to read key and cert files with readFileSync.

key is the key file.

And cert is the certificate file.

Categories
JavaScript Answers

How to fix Passport.js in Node not removing session on logout?

To fix Passport.js in Node not removing session on logout, we call the session.destroy method.

For instance, we write

app.get("/logout", (req, res) => {
  req.session.destroy((err) => {
    res.redirect("/");
  });
});

to call req.session.destroy to destroy the session.

We call it with a callback that’s called when the session is destroyed.

And we call redirect in the callback to redirect to /.