Clash Royale CLAN TAG#URR8PPP

Calling a local method inside a class in Node.js and module.export

So I have a class with functions where one is dependent on another. This class is exported with module. According to anything I can find I should be able to use "this" but that throws an error.

Example:

class Test

test()
console.log('hello');


dependentMethod()
this.test();



module.exports = Test;


This however throws these errors in node:

(node:69278) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: Cannot read property 'test' of undefined
(node:69278) [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.
(node:69278) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): TypeError: Cannot read property 'test' of undefined


It will work fine if I put the function outside the class though. Can anyone explain why this fails? :)

EDIT:

This is the code in server.js (simplified for the example) that uses the class:

const test = require(__dirname + '/server/Test');


const validator = async function(req, res, next)

const test = new test();
const serverTest = await test.dependentMethod();
next();

;

app.get('/Response/:id/:is/:userId/:hash', validator, async function (req, res, next)
//does smth



Used seperately does not work either

const test = new Test();

app.get('/Response/:id/:is/:userId/:hash', Test.dependentMethod, async function (req, res, next)
//Same error



const test = new test();

2 Answers
2

Working as expected.

Take a look here. You just need to rectify some syntactic errors.

Test.js

class Test

test()
console.log('hello');


dependentMethod()
this.test();



module.exports = Test;


Test1.js

const fileR = require('./Test.js');

const validator = async function()

const fr = new fileR();
const serverTest = await fr.dependentMethod();

;

validator();


Output:

> hello


class Test

Test

module.export

module.exports

Man, you're not showing you real code to us.

I feel that in real life you are using test.dependentMethod as middleware. And it aclually is using standalone function loosing the context. Thats's why you have an error Cannot read property 'test' of undefined.

test.dependentMethod

Cannot read property 'test' of undefined

The solution is either using test.dependentMethod.bind(test) or the code from your Edit section, where you created separate validator function and using class instances correctly.

test.dependentMethod.bind(test)

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