nats.ws: Compiling Angular code with nats.ws as dependency fails

Hi there,

first of all, thank you for your work. This repo helped us a lot.

Currently, we are using an older version of nats.ws, and when trying to update to nats.ws 1.0.0-117, we encounter a few compilation errors, such as:

Error: ./node_modules/nats.ws/nats.mjs 1070:22
Module parse failed: Unexpected token (1070:22)
You may need an appropriate loader to handle this file type, currently no loaders are configured to process this file. See https://webpack.js.org/concepts#loaders
|         this._off = 0;
|     }
>     _tryGrowByReslice = (n)=>{
|         const l = this._buf.byteLength;
|         if (n <= this.capacity - l) {
 @ ./src/app/app.component.ts 2:0-34 40:8-15
 @ ./src/app/app.module.ts
 @ ./src/main.ts
 @ multi ./src/main.ts

This is a log from trying to compile this example repo I set up, but it’s the same log in our main application.

The example repo uses Angular 11, we currently use Angular 10.

If I follow the errors and fix them, the code works, but this is not a good solution because we would need to copy the code from the dependency into our own repository and keep making the same modifications for all upcoming updates.

About this issue

Original URL
State: closed
Created 3 years ago
Reactions: 5
Comments: 16 (12 by maintainers)

Most upvoted comments

Hi @aricart, could you perhaps release a new version of this lib?

cuddlecake on Feb 1, 2021

It compiles now, but it’s still awkward to consume.

To the Angular users:

If you are using Jest for testing, you will run into another rabbit hole because of *.mjs. For now, I solves this by adding a nats.mock.ts file somewhere, with the content:

// nats.mock.ts

export const connect = jest.fn();

with usage in a test suite:

// socket.service.spec.ts
// Note that, even if you don't use it in tests, any test that indirectly imports `nats.ws` will break.

describe('My Socket Service', () => {
    connectMock = <jest.Mock>nats.connect;
    beforeEach(() => {
        connectMock.mockReset();
    })
})

and the addition to jest.config.js:

module.exports = {
    // ... other config
    transform: {
        // I think this should already be included if you are using jest for Angular
        '^.+\\.(ts|html)$': 'ts-jest',
    },
    moduleNameMapper: {
        // note that the file ending here is `.js`, not `.ts`, probably because of ts-jest
        'nats.ws': 'path/to/nats.mock.js',
    }
}

cuddlecake on Feb 9, 2021