What is the best practice of using import instead of require of called functions and reused variables - For example how should these require-lines look like as import?
const app = require('express')();
const server = require('http').createServer(app);
const io = require('socket.io')(server);
One possible way is to import the required functions and modules and use them in a next step:
import express from 'express';
import {createServer} from 'http';
import socketIo from 'socket.io';
const app = express();
const server = createServer(app);
const io = socketIo(server);
import and require both of them are good to use. But by convention in node almost use require over than import.
If you are very fond of ES6, then you can use import and other es6 features. But one thing should bear in mind that, when you are using es6, it is a good practice to bundle your code with bundeller (like webpack,babel)
Related
How do I import multiple objects/components/interfaces using the least amount of require() syntax? For example, the es6 code has this,
import express, {Express, Request, Response} from "express";
Is there something similar I can do using the require() module? Thanks in advance.
You can do something like
const express = require("express");
const {Express, Request, Response} = express;
If you don't need the express, you can do
const {Express, Request, Response} = require("express");
Choose the one that suits you better
In my jsx file, I have the following:
var express = require('express');
var myExpress = express();
var http = require('http');
var app = http.createServer(myExpress);
var { Server } = require("socket.io");
var myio = new Server(app);
However, the browser says "Uncaught TypeError: express is not a function"
I have tried importing express with an import statement, as well as making my project a module in my package.json. What is weird is that when I use the same code in a regular js file in the same folder, it works perfectly well. This code was the code in every single one of the tutorials, so I am at a loss. Thank you.
Express is node framework you can't use it in react.
I think you need https://v5.reactrouter.com/web/guides/quick-start
Let's say I want a cloud function to have a path such as:
https://[MY_DOMAIN]/login/change_password
How do I achieve the "login/" part in Node?
Or even something more complicated such as
login/admin/get_data
?
I tried using
module.exports = {
"login/change_password" = [function]
}
But I got an error when deploying and "change_password" was omitted, so it only tried to deploy a "login" function.
Another thing I tried was using express routers but that resulted in only deploying a single function, which routed to the right path (e.g. myfunction/login/change_password) which is problematic as I have to deploy in bulk every time and can't deploy a function individually.
If you want the flexibility to define routes (paths) that are more complex than just the name of the function, you should provide an Express app to Cloud Functions. The express app can define routes that add path components to the base name of the function you export from index.js. This is discussed in the documentation for HTTP functions. For example:
const functions = require('firebase-functions');
const express = require('express');
const app = express();
app.get('/some/other/path', (req, res) => { ... });
exports.foo = functions.https.onRequest(app);
In that case, all your paths will hang off of the path prefix "foo".
There is also an official samples illustrating use of Express apps: https://github.com/firebase/functions-samples/tree/master/authorized-https-endpoint
Thanks to the discussion with Doug Stevenson I was able to better phrase my question and find that it was already answered in this question.
So this would be an example of my implementation:
const functions = require('firebase-functions');
const express = require('express');
const login = require('./login.js');
const edit_data = require('./edit-data.js');
const login_app = express();
login_app.use('/get_uuid', login.getUUID);
login_app.use('/get_credentials', login.getCredentials);
login_app.use('/authorize', login.authorize);
const edit_data_app = express();
edit_data_app.use('/set_data', edit_data.setData);
edit_data_app.use('/get_data', edit_data.getData);
edit_data_app.use('/update_data', edit_data.updateData);
edit_data_app.use('/remove_data', edit_data.removeData);
exports.login = functions.https.onRequest(login_app);
exports.edit_data = functions.https.onRequest(edit_data_app);
My takeaway from this is that there is a one-to-one Express app to HTTP function correspondence, so if I wanted to have 3 different functions I would need 3 Express apps.
A good balance is to have one app and one function per module (as shown above), which also means you can separate out your functions across several modules/javascript files for ease of maintenance.
In the above example, we can then trigger those HTTP functions using
https://[DOMAIN]/login/get_uuid/
or, from the firebase functions shell
login.get("/get_uuid")
I would like to use require in a node/express app with typescript to import a json. I tried it like this:
const url = `./data/${resource}.json`;
const data = require(url);
but I get the error Cannot find module './data/my-data.json'.
I'd like to use require instead of an import in order to create the data variable dynamically depending on the value of the resource variable.
const path = require('path');
const url = path.resolve(__dirname, `./data/${resource}.json`);
const data = require(url);
The require keyword is a special keyword in nodejs. It is used to load modules, and since your json file is not a module, hence the error. Try this, this way you can dynamically load your json.
import fs from 'fs';
const file = fs.readFileSync(`./data/${resource}.json`).toString();
const data = JSON.parse(file);
There may be better ways to write this function, read mode about the fs module here.
Edit: As someone had alredy pointed out, it is actually possible to dynamicallyrequire json file. Here's how,
import path from 'path';
const uri = path.resolve(__dirname, `<path_to_json_file>`);
const data = require(uri);
However, as a standard practice, use the fs module to load static assets to your project.
import fs from 'fs';
const file = fs.readFileSync(`./data/${resource}.json`).toString();
const data = JSON.parse(file);
I have an issue where I need to load express like this:
var express = require('express');
var app = express();
In order to get .static to work:
app.use(express.static(__dirname+'views'));
Any reason why I can't use shorthand:
var app = require('express')();
When I try the short hand it says express.static is undefined and my script won't run. Is this just a feature that's not supported by express?
Any reason why I can't use shorthand:
var app = require('express')();
If you considered this statement from your script,
app.use(express.static(__dirname+'views'));
you are using static method of express.In order to use this method,you must import express first and store it in some variables like u did
var express = require('express');
From express#express.js
exports.static = require('serve-static');
static defined at class level.
then instantiate it
like this
var app = express();
to get the access to object level(prototype) method and properties like
app#use app#engine etc.
From express#application //line no 78
EDIT :
but then why can't I use app.static if I did var app = require('express')();
As I said,.static is the class level method and not the instance/object(prototype) level.
So,by var app = require('express')()
you will get express instance / object (prototype) which dont have app.static method.So,you can't use.
Read more javascript-class-method-vs-class-prototype-method
This will work: const app = (() => require('express'))()();
But you still need express itself, so there literally is no real point to requiring twice.