The `sources` field in the sourcemap seems invalid

[darrachequesne]

Hi! It seems the sources field in the sourcemap base64-arraybuffer.es5.js.map is invalid:

{"version":3,"file":"base64-arraybuffer.es5.js","sources":["../../src/index.ts"],"sourcesContent":[null],"names":[], ...

It should be ../src/index.ts I think.

node_modules/
└── base64-arraybuffer
    ├── dist
    │   ├── base64-arraybuffer.es5.js
    │   ├── base64-arraybuffer.es5.js.map
    │ ...
    ├── package.json
    ├── README.md
    └── rollup.config.ts

Not sure why though.

Related: socketio/socket.io-client#1520

[kaaax0815]

+1 This is extremely important
But the does the Source FIle even make sense, because index.ts is not included anyways

[darrachequesne]

It seems to be a known issue: rollup/rollup#4248

As a workaround, you can use the sourcemapPathTransform option in rollup.config.js:

export default {
    input: `src/index.ts`,
    output: [
        {
            file: pkg.main,
            name: pkg.name,
            format: 'umd',
            banner,
            sourcemap: true,
            sourcemapPathTransform: (sourcePath) => {
                return sourcePath.substring('../'.length);
            },
        },
    [...]
}

This produces "sources":["../src/index.ts"] instead of "sources":["../../src/index.ts"].

Update: this does not work, as src/index.ts is not included in the published package (as noted in the previous comment).

[darrachequesne]

If anyone is interested, we went ahead and forked the project: https://github.com/socketio/base64-arraybuffer

It is published as @socket.io/base64-arraybuffer@1.0.2, included in engine.io-parser@5.0.3 (and thus in latest socket.io-client, as it is a transitive dependency).

There are two additional commits:

• socketio@d30e7cc
• socketio@1584b78

We will revert back to the original package once the changes are merged here. Thanks!

[niklasvh]

Sorry for the delay. This has been fixed in 1.0.2

[darrachequesne]

It seems there is still an issue with the sourcemap file in version 1.0.2. There is no warning anymore (yay 🎉), but it seems the sourcemap isn't properly loaded.

With base64-arraybuffer@1.0.2:

With @socket.io/base64-arraybuffer@1.0.2:

It seems the sourcesContent field is ignored in the sourcemap:

{"version":3,"file":"base64-arraybuffer.es5.js","sources":["../../src/index.ts"],"sourcesContent":["const chars = 'ABCDEFGHIJKLMNOPQR...

Though that may be a bug from the source-map-loader plugin.