To get path from the request with Node.js, we get the URL from the req object.
For instance, we write
const api = express.Router();
api.use((req, res, next) => {
const fullUrl = req.protocol + "://" + req.get("host") + req.originalUrl;
next();
});
app.use("/", api);
to get the request URL’s protocol with req.protocol
We get the request URL’s host name with req.get("host").
And we get the rest of the request URL with req.originalUrl.
To use sprintf with Node.js, we use the util.format method.
For instance, we write
const s = util.format("hello %s", "world");
to call util.format to return a formatted string with %s filled in with the arguments after the first.
Therefore, s is 'hello world'.
To get the string length in bytes in Node, we call the Buffer.byteLength method.
For instance, we write
const getBytes = (string) => {
return Buffer.byteLength(string, "utf8");
};
to call Buffer.byteLength with the string to get the string‘s length in byte.
To fix MongoNetworkError: failed to connect to server [localhost:27017] on first connect with Node MongoDB, we should make sure we’re connecting to a reachable Mongo server.
For instance, we write
await mongoose.connect("mongodb://localhost/testdb");
to call mongoose.connect to connect to the testdb database on localhost.
The error shouldn’t be thrown if it’s reachable.
To Add, Delete new Columns in Node Sequelize CLI, we create a migration file.
For instance, we run
$ sequelize migration:create --name name_of_your_migration
to create a migration.
Then we write
module.exports = {
up: (queryInterface, Sequelize) => {
return queryInterface.addColumn("Todo", "completed", Sequelize.BOOLEAN);
},
down: (queryInterface, Sequelize) => {
return queryInterface.removeColumn("Todo", "completed");
},
};
to call addColumn to add a column with the table name, column name, and data type.
We call removeColumn with the table name and column name to remove it.
Then we run
$ sequelize db:migrate
to call the up function in the migration file.