Why isn't my Node package being imported? - node.js

I'm learning Node.js and am using a Node-based Azure Function.
I'm trying to bring in Chalk, to log coloured messages to the console.
However, all of the below fail (in my main index.js file).
One
module.exports = async (ctx, req) => {
const chalk = require('chalk');
return console.log(chalk.blue('Hello world!'));
Despite being the approach recommended in this answer, this results in a console error that says:
Exception: require() of ES Module C:...\node_modules\chalk\source\index.js from C:...\index.js not supported.
Instead change the require of C:...\chalk\source\index.js in C:...\index.js to a dynamic import() which is available in all CommonJS modules.
Two
If I do as the error suggests, and use
const chalk = async import('chalk')
...I then get
Exception: chalk.blue is not a function
...even though console.log(chalk) does seem to show the Chalk API and its various properties.
Three
The Chalk docs themselves recommend this:
module.exports = async (ctx, req) => {
import chalk from 'chalk'
return console.log(chalk.blue('Hello world!'));
That yields an error saying I can't use import outside of a module (but surely I'm in one?)
Four
Same as three ^^ but moving the import outside module.exports:
import chalk from 'chalk'
module.exports = async (ctx, req) => {
return console.log(chalk.blue('Hello world!'));
...yields the same error.
I'm sure this is a basic error but I can't find what I'm doing wrong so I'd be so grateful if someone could help. Thank you!

When you import something using import as a function(lazy import), It'll return an object with a default property and all exported properties. That you should use to access the module.
const module = async import('chalk')
const chalk = module.default
console.log(chalk.red('Hello world!'))

Related

Typescript error when using require - This expression is not callable. Type 'typeof import(...)' has no call signatures.ts(2349)

I'm trying to run this script
const fetch = require('node-fetch');
function test() {
fetch('https://google.com')
.then(res => res.text())
.then(text => console.log(text))
}
test();
But i get this error
This expression is not callable.
Type 'typeof import("(...)/node_modules/node-fetch/#types/index")' has no call signatures.ts(2349)
although it works when i use import
import fetch from 'node-fetch';
why and how to fix it?
As per spender's comment, you can change the require to use this destructuring:
const {default : fetch} = require('node-fetch');
This has worked for me in a similar situation (using axios in node, which has a similar API)
If your are using globby or other library that uses a syntax similar to this:
import globby = require('globby');
Change it to this
import { globby } from 'globby';

how can I use npm "debug" package with es modules

this is how I used to used it in common modules.
const debuger=require('debug')("namespace")
I set an environmental variable DEBUG="namespace" and when i start the app, i can use the debugger.
However I could not figure out how to use it with import/export staments.
import debugger from "debug" // how can i pass () here
You can do:
import debug from 'debug';
const logger = debug('namespace');
logger('Starting App');
Actually, as the npm debug module exports a function directly (module.exports = (params) => {...), you can give the function whatever name you like, for example:
import createDebugMessages from 'debug';
const debug = createDebugMessages('namespace');
debug('Starting App');
This way, the original syntax for debugging does not even need to be changed.

Cypress: Cannot use cy.task() to load dataset to Mongo before tests

I'm trying to use cy.taks() to load certain datasets to mongo before a test is run. But I'm getting errors. I've got a module where I export 2 functions, one from dropping a collection, and the other to load an object to a collection. Here is my cypress/plugins/index.js:
module.exports = (on, config) => {
on("task", {
"defaults:db": () => {
const {dropCollection, createUser } = require("../../lib/connectDB");
dropCollection("users");
createUser(userData)
},
});
};
Here is my /lib/connecDB.js:
export function dropCollection(collection) {
return mongoose.connection.dropCollection(collection);
}
export async function createUserInDB(userData) {
await User.create(userData);
}
So when I run the test, I'm getting:
cy.task('defaults:db') failed with the following error:
Unexpected token 'export'
Tried as well importing these function outside the index.js export, but getting same result.
I'd say it is something about export/import. The functions are exported as ES6, and imported as ES5.
I've tried to import the function the ES6 like:
import { dropCollection, createUser } from '../lib/connectDB'
And then export the plugin function also as ES6, but then I get:
Error: The plugins file is missing or invalid.
Your `pluginsFile` is set to `C:\Users\someRoute\cypress\plugins\index.js`, but either the file is missing, it contains a syntax error, or threw an error when required. The `pluginsFile` must be a `.js`, `.ts`, or `.coffee` file.
I've also tried to import required modules outside the function like:
const globalDbUtils = require('../lib/connectDB')
And then use the functions as
globalDbUtils.dropCollection("collectionName")
globalDbUtils.createUser(userData)
But I'm getting last error. I've tried pretty much everything, I tried to import Mongoose models straight, mongo client etc...Also I tried to import just one function and return it (just copy/pasting official doc...) but cannot make it work. I researched for a couple of days getting nothing, I found there is a npm package that helps u doing this, but since cypress allows you to do this by using no more plugins, I'd like to do it with no more tools than cypress itself.
Anyone knows what I am doing wrong?
Thanks in advance!
You need to use require instead of import at the top of your file and when exporting at the bottom use
module.exports = { createUserInDB }
Instead of exporting as you are currently doing.

NodeJS - using require works import does not work

I'm trying to understand why require works while import does not for an npm package. The package is r7insight_node and allows us to send our logs to their product, Rapid7. When we use require as per their instructions things work fine, but don't when I use import.
Their library has an src/index.js file that looks like:
// Use codependency for dynamically loading winston
const requirePeer = codependency.register(module);
// Import winston
const winston = requirePeer('winston', {optional: true});
const Transport = requirePeer('winston-transport', {optional: true});
// If we have successfully loaded winston (user has it)
// we initialize our InsightTransport
if (winston) {
provisionWinston(winston, Transport);
}
// Logger is default export
module.exports = Logger;
// Export as `bunyanStream` to not break existing integration
module.exports.bunyanStream = buildBunyanStream;
module.exports.provisionWinston = provisionWinston;
My understanding is that require is synchronous and is "computed" whereas import is asynchronous and is NOT "computed" as written here. Is this the reason for why require works while import does not?
Does "computed" mean in that the index.js file is executed and hence the if (winston) block is checked and executed in a require but not in an import? Is there a way to achieve the same using import statements?
Thanks in advance
for the package to work with the ES6 import way, it has to be written to it, it has to be exported as eg:export default Logger and not module.exports = Logger, hope my answer helped you

Testing async methods using Mocha, Chai, node.js

I have a very simple code structure like this
TestWorks.ts
const axios = require('axios');
export class TestWorks{
async getUsersList(param1:TestModel, userDetail:any){
console.log("BEGIN -- ... ");
And then this is my test class
MyTest.ts
const testworks = require("../src/interfaces/TestService/TestWorks");
it('Get Users', async () => {
var x = await testworks.getUsersList({}, {});
expect(x).to.be.an("object");
});
but I am seeing the following error, unable to figure out what the issue could be. The paths are definitely right, not an issue with the file paths of where the files are
Get Users:
TypeError: testworks.getUsersList is not a function
at C:\Users\xxxxxx\Documents\xxxxx\test\test-server.test.ts:53:28
testworks refers to the module (or whatever TypeScript exports) because you use require(). You should use import for TypeScript modules.
import { TestWorks } from '../src/interfaces/TestService/TestWorks';

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