When using Angular2/TypeScript: TypeError: exists is not a function

[philoliver]

Hi,
I have an Angular CLI project running in Electron. When I follow your instructions and import the module like this import NFC from '../../../node_modules/nfc-pcsc';, and call const nfc = new NFC(minilogger);, then I get the following error in the console:

TypeError: exists is not a function

And during the build process

WARNING in ./~/bindings/bindings.js
76:22-40 Critical dependency: the request of a dependency is an expression

[philoliver]

I did some research and found out that the TypeError: exists is not a function appears to be a bug in the node-bindings module. See: TooTallNate/node-bindings#20

It should be fixed when the new release is available on NPM.

However, going one step further, this fix will still not make the it work when using AngularCLI/Webpack. To make it work in this scenario we would need to use node-loader instead of node-bindings to load the binding file.

I did the following change to make it work locally:

"dependencies": {
  "bindings": "github:tootallnate/node-bindings#pull/20/head", < Instead of this,
  "node-loader": "^0.6.0", << use this
  "nan": "^2.5.1"
},

Then edited "/node_modules/@pokusew/pcsclite/lib/pcsclite.js"
const pcsclite = require('node-loader!./../build/Release/pcsclite.node');

[pokusew]

Hi @philoliver

Thank you for posting your problem.

I am quite busy now, but I'll look at it today or tomorrow.

[tobinbc]

Hi @philoliver @pokusew
Just to let you know that I have had exactly the same error and this fixed it also. Currently using a gulp task to search + replace the code post install. Thanks @philoliver for finding the fix!
Cheers

[dhruv217]

Updating the node-binding to 1.3.0 does not seem to have solved the issue as @philoliver pointed out. Is there a permanent solution to this problem instead of using gulp because i am a noob and am not familiar with it.
Thanks for the awesome lib by the was. If not for this I would not be able to make my code platform independent.
I am using an Electron app with angular 4 to read and write data in nfc tags.

[pokusew]

Hi @dhruv217,

I think it should work. Check out Can I use this library in my angular-electron app? in FAQ section of the README. In the linked #24 (comment), there is described what needs to be done in order to make it work.

It is related to the angular-electron boilerplate, but I think, that's what you are using in your project https://github.com/dhruv217/shrabik-smart-card-reader.

Please let me know, if it works for you. If you encounter any problems feel free to contact me. 🙂
I am available for chat here https://discord.gg/bg3yazg.

Hope it helps. 🙂

---

PS Don't forget to star ⭐️ my library, if you find it useful. 😃 Thanks.

[Canos]

@philoliver thanks for your contribution.
After making your changes proposed above i've got this error

Uncaught Error: Cannot open /***/node_modules/@pokusew/pcsclite/build/Release/pcsclite.node: 
TypeError: Cannot read property 'dlopen' of undefined
    at Object.<anonymous> (pcsclite.node:1)
    at Object../node_modules/node-loader/index.js!./node_modules/@pokusew/pcsclite/build/Release/pcsclite.node (vendor.js:72750)
    at __webpack_require__ (bootstrap:78)
    at Object.<anonymous> (pcsclite.js:4)
    at Object../node_modules/@pokusew/pcsclite/lib/pcsclite.js (pcsclite.js:197)
    at __webpack_require__ (bootstrap:78)
    at Object../node_modules/nfc-pcsc/dist/NFC.js (NFC.js:8)
    at __webpack_require__ (bootstrap:78)
    at Object../node_modules/nfc-pcsc/dist/index.js (index.js:145)
    at __webpack_require__ (bootstrap:78)

i'm frozen here, dont know how to continue.
i'm using Angular 7.2 and electron 5.0.1

any idea?

[naveed-31]

I facing the similar issue ,any update on this issue ??

[ssteiger]

+1 👍

[henrysha]

Any updates?

[kablin]

+1
I try philoliver solution and got

Uncaught Error: node-loader:
TypeError: process.dlopen is not a function

[nmattela]

+1
I tried philoliver's solution as well and got:

./node_modules/@pokusew/pcsclite/build/Release/pcsclite.node (./node_modules/node-loader/dist/cjs.js!./node_modules/@pokusew/pcsclite/build/Release/pcsclite.node)
TypeError: this.getOptions is not a function