Warning due to incomplete sourcemaps

[schnerd]

Description

The sourcemaps in the published package reference files that are not included in the published package.

When I use this package in my create-react-app project, I see the following warning:

WARNING in ./node_modules/@microsoft/fetch-event-source/lib/esm/fetch.js
Module Warning (from ./node_modules/source-map-loader/dist/cjs.js):
Failed to parse source map from '/[REDACTED]/node_modules/@microsoft/fetch-event-source/src/fetch.ts' file: Error: ENOENT: no such file or directory, open '/[REDACTED]/node_modules/@microsoft/fetch-event-source/src/fetch.ts'

fetch.js has //# sourceMappingURL=fetch.js.map. And fetch.js.map starts as follows:{"version":3,"file":"fetch.js","sourceRoot":"","sources":["../../src/fetch.ts"],"names":[],"mappings":";;;;;;;;;;;AAAA,OAA.

The "sources":["../../src/fetch.ts"] points to a file that doesn't exist in the package, which causes the warning to be emitted.

Proposed solution

Either (a) include the src directory in the published package, or (b) update tsconfig to inline the ts file content using the inlineSources option

Steps to reproduce

1. Scaffold new app using create-react-app npx create-react-app my-app
2. npm install --save @microsoft/fetch-event-source
3. Add import {fetchEventSource} from '@microsoft/fetch-event-source to top of index.js
4. npm run start, warnings should show

[sureshHARDIYA]

I am also having same issue. Any solution would be appreciated.

[schnerd]

@vishwam @firedog1024 Do you plan to maintain and accept PRs for this repo (e.g. #23)? Otherwise our team may just fork it if fixes won't be merged in.

[inad9300]

Idem.

[OldManMeta]

Any solutions for this???

[ziyoung]

There's a workaround.

If you are using webpack, set ignoreWarnings option to skip parse error. https://webpack.js.org/configuration/other-options/#ignorewarnings

module.exports = {
  // ...
  ignoreWarnings: [/Failed to parse source map/]
}

If you are using custome-cra, add the following code in config-overrides.js.

const addIgnoreWarnings = (_loaderOptions) => config => {
  // https://github.com/facebook/create-react-app/blob/0a827f69ab0d2ee3871ba9b71350031d8a81b7ae/packages/react-scripts/config/webpack.config.js#L353
  const loader = config.module.rules.find(({
    enforce, loader
  }) => enforce === 'pre' && typeof loader === 'string' && loader.includes('source-map-loader'));
  if (loader) {
    if (!config.ignoreWarnings) {
      config.ignoreWarnings = [];
    }
    config.ignoreWarnings.push(/Failed to parse source map/,)
  }
  return config
}


module.exports = {
  webpack: override(
    // ...
    addIgnoreWarnings(),
  )
};

[jordanarldt]

This is still an issue

[peplocanto]

MS doin' MS, I suppose...

[dargmuesli]

You might want to check out extended-eventsource as potential new replacement. It's codebase looks proper.

[Calamari]

So, what's the solution here? Is this project abandoned I should use something else?
The problem obviously still exists…

[woutkonings]

Also having this issue...

[motin]

See linked issue comment shafkevi/lambda-bedrock-s3-streaming-rag#1 (comment) above - SSE events can be streamed directly using nothing but fetch, making fetch-event-source unnecessary.