Category: JavaScript Answers

Sometimes, we want to fix Node.js connect only working on localhost.

In this article, we’ll look at how to fix Node.js connect only working on localhost.

How to fix Node.js connect only working on localhost?

To fix Node.js connect only working on localhost, we can call listen with '0.0.0.0'.

For instance, we write

const app = connect().use(connect.static("public")).listen(3000, "0.0.0.0");

to call listen with '0.0.0.0' to listen to traffic from outside localhost.

Conclusion

To fix Node.js connect only working on localhost, we can call listen with '0.0.0.0'.

Sometimes, we want to fix the JavaScript heap out of memory error when running npm install.

In this article, we’ll look at how to fix the JavaScript heap out of memory error when running npm install.

How to fix the JavaScript heap out of memory error when running npm install?

To fix the JavaScript heap out of memory error when running npm install, we can run npm install with an increased memory limit.

For instance, we run

node --max-old-space-size=8000 $(which npm) install -g ionic

to set the max-old-space-size 8000 MB before running npm install to install the ionic package.

Conclusion

To fix the JavaScript heap out of memory error when running npm install, we can run npm install with an increased memory limit.

Sometimes, we want to get Express.js to send 404 only on missing routes.

In this article, we’ll look at how to get Express.js to send 404 only on missing routes.

How to get Express.js to send 404 only on missing routes?

To get Express.js to send 404 only on missing routes, we can add a catch-all route at the end of the app.

For instance, we write

const express = require("express");
const app = express.createServer();

const users = [{ name: "abc" }];

app.all("/user/:id/:op?", (req, res, next) => {
  req.user = users[req.params.id];
  if (req.user) {
    next();
  } else {
    next(new Error("cannot find user ", req.params.id));
  }
});

app.get("/user/:id", (req, res) => {
  res.send("viewing " + req.user.name);
});

app.get("/user/:id/edit", (req, res) => {
  res.send("editing " + req.user.name);
});

app.put("/user/:id", (req, res) => {
  res.send("updating " + req.user.name);
});

app.get("*", (req, res) => {
  res.send("not found", 404);
});

app.listen(3000);

to add

app.get("*", (req, res) => {
  res.send("not found", 404);
});

at the end of the app to add a catch all route with a route handler that only runs when no other URLs listened above it is matched.

We call res.send to send a 404 response.

Conclusion

To get Express.js to send 404 only on missing routes, we can add a catch-all route at the end of the app.

Sometimes, we want to set default path (route prefix) in Express.

In this article, we’ll look at how to set default path (route prefix) in Express.

How to set default path (route prefix) in Express?

To set default path (route prefix) in Express, we can create a Router instance.

For instance, we write

const router = express.Router();
router.use("/user", user);

app.use("/api/v1", router);

to call express.Router to create a router.

Then we call router.use with a user route object.

Next, we call app.use with router to use the router in the app.

Therefore, we access the routes in the user router by prepending /api/v1/user to the URL.

Conclusion

To set default path (route prefix) in Express, we can create a Router instance.

Sometimes, we want to get the whole response body when the response is chunked in Node.js.

In this article, we’ll look at how to get the whole response body when the response is chunked in Node.js.

How to get the whole response body when the response is chunked in Node.js?

To get the whole response body when the response is chunked in Node.js, we an listen to the on and end events.

For instance, we write

request.on("response", (response) => {
  let body = "";
  response.on("data", (chunk) => {
    body += chunk;
  });
  response.on("end", () => {
    console.log(body);
  });
});
request.end();

to call request.on with 'response' to listen for the response.

Then we call response.on with 'data' to listen for the response chunks and append them to body.

Next, we listen to the end event with a callback that runs when we got the whole response, so we log the full response body in the callback.

Conclusion

To get the whole response body when the response is chunked in Node.js, we an listen to the on and end events.