I am requiring a module and saving it in a variable. But when I call a module function by wrong name, it does not throw any error or consoles any error. How do I make this throw error?
var module = require('../pre_process/' + preProcessFolder + '/' + preProcessModule);
// module -> { XYZ: [Function] }
//Following does not throw error and doesn't console anything.How to handle/debug this error
module['XY'](result, userId)
.then(function(recData) {
})
I am using q library for promise.
So you want to check if a function (provided by a modul) exists.
You could use try like the example here:
Javascript check if function exists
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'm trying to find the file of included modules. From the main module, require.resolve('module') happily returns me the value of the main key from the module's package.json.
However, I would like to do this from a module that's been included via npm. If I simply call require.resolve('module'), it looks in the node_modules for this module, whereas I need to resolve it from the point of view of the running package.
According to the docs, require is actually module.require and module.parent returns the module that first required this one. Why then does module.parent.require.resolve('module') not work? I get ana
error:
TypeError: module.parent.require.resolve is not a function
Oddly though, console.log module.parent.require.toString() returns
function (path) {
assert(path, 'missing path');
assert(typeof path === 'string', 'path must be a string');
return Module._load(path, this, /* isMain */ false);
}
so it certainly looks like a function to me.
Anyone know what's going on? I've also tried require.main.require.resolve() and that does a very similar thing.
TypeError: module.parent.require.resolve is not a function
Oddly though, console.log module.parent.require.toString() returns ...
module.parent.require is a function, module.parent.require.resolve is not.
Why is resolve() not a function?
It appears require() and module.require() are not the same:
console.log(require === module.require); // false
For the curious:
console.log(module.require.toString())
function (path) {
assert(path, 'missing path');
assert(typeof path === 'string', 'path must be a string');
return Module._load(path, this, /* isMain */ false);
}
console.log(require.toString())
function require(path) {
try {
exports.requireDepth += 1;
return mod.require(path);
} finally {
exports.requireDepth -= 1;
}
}
So require() calls module.require(), but is not the same thing.
What about resolve()?
We know require.resolve is a function:
console.log(require.resolve.toString())
function resolve(request) {
return Module._resolveFilename(request, mod);
}
But module.require.resolve is not:
console.log(module.require.resolve)
undefined
So unfortunately resolve() is only available at require.resolve(), and not at module.require.resolve() (or module.parent.require.resolve() for that matter).
Solution?
Not a great solution, but you could try manually calling Module._resolveFilename() and passing in the parent module instead of the current module:
const Module = module.constructor;
const fileName = Module._resolveFilename('module', module.parent);
This solution isn't great because it relies on internal API functions that could possibly change in the future. It would be nice if NodeJS would provide better documentation and APIs for module loading/resolving.
I have a module that writes to a log file. (coffeescript sorry, but you get the idea!)
require = patchRequire(global.require)
fs = require('fs')
exports.h =
log: ()->
for s in arguments
fs.appendFile "log.txt", "#{s}\n", (e)->
if (e) then throw e
It works file when I call it directly. But when I call it from a callback, for example casperjs start event:
h = require('./h').h
casper = require('casper').create()
casper.start "http://google.com", ()->
h.log("hi")
casper.run()
... I always get this or similar "undefined" TyepError:
TypeError: 'undefined' is not a function (evaluating 'fs.appendFile("log.txt", "" + s + "\n", function(e) {
if (e) {
throw e;
}
})')
Googling this doesn't give many clues!
CasperJS runs on PhantomJS (or SlimerJS) and uses its modules. It is distinct from nodejs. PhantomJS' fs module doesn't have an appendFile function.
Of course you can use fs.write(filepath, content, 'a'); to append to a file if used in casper. If you still want to use your module both in casper and node then you need to write some glue code like
function append(file, content, callback) {
if (fs.appendFile) {
fs.appendFile(file, content, callback);
} else {
fs.write(file, content, 'a');
callback();
}
}
I think the problem is with the coffeescript. Try using a splat parameter instead of relying on the arguments object.
log(statements...)
If that doesn't work, you might need to look at the javascript output or try the same thing in plain JavaScript and see if you get the same error.
I am trying to modify require like this
require = function (path) {
try {
return module.require(path);
} catch (err) {
console.log(path)
}
}
However, scope of this modification is only in the current module. I want to modify it globally, so every module that is required by this module will also get the same copy of require function.
Basically, I want to catch SyntaxError to know which file has problem. I can't seem to find any other alternative. If I put module.require in try/catch block, I'll be able to get the file name which caused SyntaxError.
I managed to solve it by modifying prototype function require of Module class. I put this in the main script and its available to all the required modules.
var pathModule = require('path');
var assert = require('assert').ok;
module.constructor.prototype.require = function (path) {
var self = this;
assert(typeof path === 'string', 'path must be a string');
assert(path, 'missing path');
try {
return self.constructor._load(path, self);
} catch (err) {
// if module not found, we have nothing to do, simply throw it back.
if (err.code === 'MODULE_NOT_FOUND') {
throw err;
}
// resolve the path to get absolute path
path = pathModule.resolve(__dirname, path)
// Write to log or whatever
console.log('Error in file: ' + path);
}
}
Why don't you use a try-catch block inside your code and once an error occurs to check the stack trace. Check out these links
How to print a stack trace in Node.js?
http://machadogj.com/2013/4/error-handling-in-nodejs.html
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').