Category: JavaScript

To redirect to URL with Node.js, we use the res.redirect method.

For instance, we write

res.redirect("your/404/path.html");

to call res.redirect with the path to redirect to with Express.

To add a single routing handler for multiple routes in a single line with Node.js Express.js, we call the route method with an array of routes.

For instance, we write

app.get(
  [
    "/test",
    "/alternative",
    "/bar*",
    "/foo/:farcus/",
    "/hoop(|la|lapoo|lul)/poo",
  ],
  (request, response) => {}
);

to create a get route handler that accepts requests from the URLs listed in the array.

To pipe a stream to s3.upload() with Node.js, we call the stream.PassThrough constructor.

For instance, we write

const uploadFromStream = (s3) => {
  const pass = new stream.PassThrough();
  const params = { Bucket: BUCKET, Key: KEY, Body: pass };
  s3.upload(params, (err, data) => {
    console.log(err, data);
  });

  return pass;
};

inputStream.pipe(uploadFromStream(s3));

to define the uploadFromStream function.

In it, we create a PassThrough object.

Then we call upload with the params object to upload the stream data.

Next, we call pipe with the PassThrough object returned by uploadFromStream to upload the inputStream data.

To use Mongoose to update values in array of objects with Node.js, we use the $set operator.

For instance, we write

Person.update(
  { "items.id": 2 },
  {
    $set: {
      "items.$.name": "updated",
      "items.$.value": "two updated",
    },
  },
  (err) => {}
);

to call update with an object with $set set to an object with the fields in the item with id 2 to update.

The item being updated is the object in items with id 2.

We update the name and value fields of it.

To get the sha1 hash of a string in Node.js, we use the crypto module.

For instance, we write

const crypto = require("crypto");
const shasum = crypto.createHash("sha1");
shasum.update("foo");
const hash = shasum.digest("hex");

to call createHash to create a hash.

Then we call update to add content to it.

Finally, we call digest with 'hex' to return the hash.