Can anyone explain the following 2 lines of code from a node project as I'm very much new to Node.js. I know how to export a function or constant and to import those in node.js but following style I have never seen before.
require = require("esm")(module);
module.exports = require("./src");
These two lines are written in the index.js file in the root folder which seem to be triggering something.
Thanks.
Related
So I've inserted pictures of my vsCode, I'm trying to use node (or nodemon, which never seems to work for me) how ever I get an error message each time. I've even tried moving around my code, any assistance would be greatly appreciated!
Change line 2 of app.js into
const hotel = require('./models/hotel.js/hotel');
The reason you got an error in the console was because the require directory is wrong.
I used this library, mem-fs-editor (https://github.com/sboudrias/mem-fs-editor), in a Yeoman generator a few weeks ago. It worked nicely, but now I tried to use it again in a different scope and I couldn't do anything. Obs: I used it because this is the library Yeoman provides to handle the file system.
In Yeoman Generators we can copy files from a template folder, passing values to inject in the code, to a different folder. And that's precisely what I need, but I can't use Yeoman this time.
I tried the same code I used in my Yo Generator, but it don't work. So I'm not sure how mem-fs works. No errors are thrown and even the code provided by the author of the project don't work to me.
I tried this (and some other things with copyTpl) with no success
var memFs = require('mem-fs');
var editor = require('mem-fs-editor');
var store = memFs.create();
var fs = editor.create(store);
console.log(fs.write('./somefile.js', 'var a = 1;'));
Anyone knows how it works or what else I can do to make this happen?
mem-fs-editor author here.
mem-fs stands for memory file-system. All the files you creates are stored in memory and won't get written to disk until you call:
editor.commit(callback);
Yeoman does that automatically for you. It is this way with Yeoman to collide every file changes together and then being able to only prompt for file conflicts once (rather than everytime a single file is being written to).
Im really new to node and feel like I understand nothing. I was watching a tutorial where the fs.writeFileSync creates a new file. However my code doesn't work and no file is being created-does someone know why? Also why do I need
var fs=require("fs");
? As I understand fs is a build in module and if we require something, there should be another file that exports something (which we require using the fs module)? Node is kind of hard to understand and would appreciate some explanation! Thanks
var fs=require("fs");
fs.writeFileSync("contents.txt","Thats a new file")
console.log(fs.writeFileSync("contents.txt").toString());
fs is indeed a node built-in module, and as other modules, you must require it to use its capabilities. the file you're referring is present internally, so you don't have to npm install it.
And regarding your code, fs.writeFileSync should work as you used it, however, when you tried to print it, you used this function again, this time with no contents, what probably caused the mix-up.
Code that should work perfectly is:
//Requiring the fs module in order to use it later on
var fs = require('fs');
//Writing "Thats a new file" as text to a new file called "contents.txt" in the same directory as the script file.
fs.writeFileSync('contents.txt', 'Thats a new file');
//If you want to print the file, read it, like so.
console.log(fs.readFileSync('contents.txt'));
Also, I think you should continue reading about node's async capabilities so you can understand better this technology and what is it good for. This is one site you can learn from but there are a lot of other good ones out there.
for some reason I can't get my require to work, it should just find both models fine but the path for the file just won't work.
app
models
user.js
match.js
server.js
Seems like a simple fix but cannot seem to do it myself right now. I'm using (var User = require('/app/models/user.js');)
Thanks guys.
Actually you also can write it as,
var User = require('./app/models/user')
without even putting .js at the end, as it is added by default.. Just a tip to know :)
and here ./ means the current directory.
Hope it helps :)
I am new here and pretty new to Node.js. I got Express working fine, connecting to MySQL (database) is going fine, and socket io is working fine.
But I decided to split many of these features up in separated files. To keep my main JS file nice and clean. I made it possible to get variables from other js files back to my main.js script. Either using exports, or global. I find global working easier since most of them are functions. It's all working fine to this point.
But now the issue that I am having. I'm loading 3 js files in my main.js file. I am requiring the first js file, I call the function that is in that js file and store the result in a variable. That's going fine. But now the second js file is suppose to use or grab this variable, and that isn't working.
My question is, how do I make that work?
It is a matter of your design.
You should use module.exports to return a variable from a file.
Example:
file1.js
function someFunction() {return true;}
module.exports = someFunction();
main.js
console.log(require('./file.js')); // true
So, if the second file depends on the variable from the first file, you may also require the file1.js in the second one.
Or, export a function that accept one parameter in the second file. The main file should then use the variable from first file to call the function.