The following code works perfectly fine when I use bluebird promises:
import * as Promise from 'bluebird';
getAccount(id) {
var account = find(accounts, ['id', id]);
return account ?
Promise.resolve(account) :
Promise.reject(new NotFoundError());
}
NotFoundError is defined as follows:
export function NotFoundError(message = 'Not Found') {
this.name = 'NotFoundError';
this.message = message;
this.stack = (new Error()).stack;
}
NotFoundError.prototype = Object.create(Error.prototype);
NotFoundError.prototype.constructor = NotFoundError;
However, if I remove the import of bluebird in getAccount() and let node.js take over promises, the code fails inside the NotFoundError() constructor because this is not defined. Specifically, the constructor is called twice, once correctly from the getAccount() code shown above and a second time by node.js's _tickCallback() function with this as undefined:
NotFoundError (errors.js:13)
runMicrotasksCallback (internal/proces…ext_tick.js:58)
_combinedTickCallback (internal/proces…ext_tick.js:67)
_tickCallback (internal/proces…ext_tick.js:98)
Why is node.js calling the NotFoundError() constructor a second time and that too incorrectly!!!
Please help.
The issue is caused by this line:
.catch(NotFoundError, function() { ... })
Native promises don't have an option to pass a specific error class to a catch method, so what happens is that when an error occurs, NotFoundError is called (without a new in front of it) because it's presumed to be the catch handler.
Related
I have tried this code :
const invNum = require('invoice-number');
router.post('/checkout', async (req, res, next) => {
if (!req.session.cart) {
return res.redirect('/pos/');
}
var saleList = Sale.find().sort({ _id: -1 }).limit(1); // removed (err, data)=>{} to simply view it is working tested already
var settings = await Setting.find({}); // removed try and catch to simply view it is working tested already
var ticketNumber;
ticketNumber = !saleList ? invNum.next('0000000') : invNum.next(saleList.ticket_number);
var sale = new Sale({
ticket_number:ticketNumber,
cart: req.session.cart,
created_at: new Date()
});
sale.save((err, product) => {
createReceipt(settings, req.session.cart, "receipts/"+ticketNumber+".pdf");
req.session.cart = null;
res.redirect('/pos/');
});
});
I got this error:
TypeError: invNum.next is not a function
The problem is with invNum.next().
invNum.next() is a Node.js module to generate invoice number sequentially installed from npm.
Example:
invNum.next('2017/08/ABC001')
// => 2017/08/ABC002
I have tried already suggestions from previous stackoverflow posts by trying Promises or await async function in order to get this code to work. Hopefully, you can help or suggest something. Thank you.
There is a problem in version of invoice-number module. In the npm it is showing as 1.0.6 but in the GitHub repository it has 1.0.5 in the package.json file.
https://github.com/amindia/invoice-number.
I have tested this module by taking from Github repository and it's working fine.
Please take the source of this module from the given link it will works fine.
Seems to be some error in the module. I tried the below code snippet on RunKit
https://runkit.com/embed/ws2lv1y38mt4
var invNum = require('invoice-number')
try{
invNum.next('sdfsd1')
} catch(e){
console.log(e)
}
Getting the same error
I got this error:
TypeError: invNum.next is not a function UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch()
What is the output when you use the console.log on invNum?
Also use try catch and inside call invNum.next with await. Maybe something inside this function is throwing an error.
Edit: as jfriend00 says, if an plain text (like your "0000...") is working, probably the saleList is returning some error and you are not catching or treating the error.
Edit2: The last update on this NPM code is from 1 year ago and fewer people used this lib, probably is broken.
There is some part of the code from the index.js of the lib:
function _next (invoiceNumber) {
if (!invoiceNumber)
throw new Error('invoiceNumber cannot be empty')
var array = invoiceNumber.split(/[_/:\-;\\]+/)
var lastSegment = array.pop()
var priorSegment = invoiceNumber.substr(0, invoiceNumber.indexOf(lastSegment))
var nextNumber = alphaNumericIncrementer(lastSegment)
return priorSegment + nextNumber}
var api = { next: _next}
module.exports = api
I have a typescript application running on node.
I am using 'EventEmitter' class to emit a change in variable value.
This is my piece of code,
import events from 'events';
public async updateStream(streamContext: string, state: boolean): Promise<string> {
const eventEmitter = new events.EventEmitter();
if (state === true) {
return StreamManagement.instance.activeStreams.get(streamContext).streamState = 'Paused';
} else {
const streamState = StreamManagement.instance.activeStreams.get(streamContext).streamState = 'Active';
eventEmitter.emit('resume');
return streamState;
}
}
public async waitForStreamActive(stream: Stream) {
const eventEmitter = new events.EventEmitter();
// tslint:disable-next-line:no-unused-expression
return new Promise(( resolve ) => {
eventEmitter.on('resume', resolve );
});
}
This piece of code builds fine. But when i run the code, as in execute the operation, I am getting the following error,
error: errorHandler - Apply - Hit Unhandled exception {"timestamp":"2019-04-29T12:33:49.209Z"}
error: errorHandler - Apply - Cannot read property 'EventEmitter' of undefined - TypeError: Cannot read property 'EventEmitter' of undefined
at StreamResource.updateStream (C:\Vertigo\core\reference_platform\dist\index.js:10695:51)
at StreamService.patchStream (C:\Vertigo\core\reference_platform\dist\index.js:22524:40)
at process._tickCallback (internal/process/next_tick.js:68:7) {"timestamp":"2019-04-29T12:33:49.215Z"}
What am I doing wrong?
I've set up minimal project to reproduce it and immediately ts compiler warns me about:
TS1192: Module '"events"' has no default export.
But this seems to work:
import * as EventEmitter from 'events'
new EventEmitter();
I'm using NodeJS 8 LTS.
I have 3 js scripts where:
// main.js
const dom = require ('./Domains/Domains');
const factory = require ('./Domains/Factory');
(async () => {
const Domain = await factory.foo(); // <=== Error
})();
// Domains.js
class Domains {
constructor (options = {}) {
....
}
}
module.exports = Domains;
// Factory.js
const Domains = require('./Domains');
module.exports = {
foo: async () =>{
.... async stuff ...
return new Domains();
}
};
when I run main.js I get
(node:1816) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: Domains is not a constructor
warning.js:18
(node:1816) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
Debugging, I found that in Factory.js when it requires Domanis.js const Domains = require('./Domains'); it returns an empty object.
Looking around on internet I found that it happens when there are a circular dependencies between modules (Require returns an empty object) but It doesn't seem the case here.
Any idea?
Finally, I got the the issue's origin. The empty object was due to a circular dependency derived by another require that was inside Domains.js
// Domains.js
const another_module= require("circular_dep_creator");
class Domains {
constructor (options = {}) {
....
}
}
module.exports = Domains;
// circular_dep_creator.js
const factory = require ('./Domains/Factory');
...
another stuff
So, this causes a circular dependency that creates an empty object
The setImmediate call will delay the loading of the required module until the browser has finished doing what it needs to do. This may cause some issues where you try to use this module before it is loaded, but you could add checks for that.
// produces an empty object
const module = require('./someModule');
// produces the required object
let module;
setImmediate(() => {
module = required('./someModule');
});
I'm trying to unit test that a method gets called in my module. The class and method are private and not exposed using module.exports. The modules I'm using for the tests are: mocha, rewire, assert, sinon.spy. The call I want to test is my error method, this currently throws an error, but might change later - so I don't want to test that an error is thrown, just test that class.error() gets called. Not sure how to procede and have tried numerous tuts online.
The class is (currently accessed in tests using rewire):
var MyClass = function MyClass(o){
var self = this
if(!o || typeof o !== 'object')
self.error('No configuration passed to MyClass')
}
MyClass.prototype.error = function(msg){
throw Error(msg)
}
My test currently, which is not working:
it('Constructs MyClass', function(done){
//check constructs normally (this passes and works)
var actual = obj.__get__("MyClass.config")
assert.deepEqual(actual, config)
/**
* check calls error method
*/
//stub class.error ?
//construct class without config
//check if class.error is called
done()
})
In pseudo code, what I'm hoping to do is:
var stub = stub(MyClass)
->do('construct', null) //no config passed
->didCall('error') //check error method is called
This may be a duplicate of: Mocking modules in Node.js for unit testing
But it is throwing an error me: Object #<Object> has no method 'expect'
To solve it I imported the private class constructor using rewire, then I overrode the error method, setting it as a sinon.spy. I construct the class, then check if the spy was called:
//check calls error method if no config passed
var obj = rewire('./path/to/my/module')
, MyClass = obj.__get__("MyClass")
, spy = sinon.spy()
MyClass.prototype.error = spy
var foo = new MyClass()
assert.equal(spy.called, true)
done()
I'm using node-webkit with an external module called edge.
According to the node-webkit docs modules that contain native code must be recompiled using nw-gyp as oppose to node-gyp. I was able to recompile without error and node-webkit seems to import the module OK.
Heres my code. The code I'm trying to use:
var edge = require('edge.node');
var hello = edge.func(function () {/*
async (input) =>
{
return ".NET welcomes " + input.ToString();
}
*/});
hello('Node.js', function (error, result) {
if (error) throw error;
console.log(result);
});
Which throws the following error when run within node-webkit.
Uncaught TypeError: Object [object Object] has no method 'func'
If write the object out to console.log I can see:
Object {initializeClrFunc: function}
initializeClrFunc: function () { [native code] }
__proto__: Object
So the module seems to have loaded. If I run the same code outside of node-webkit, everything works perfectly and I can access the func function. This is driving me crazy - and any help would be really appreciated.
func method is provided by edge.js, the wrapper around edge.node native module. So you should replace require('edge.node') by require('edge').