es5-build file has spread operator in code (and erroring in IE 11)

[pydolan]

I'm seeing a "Syntax error" at line 11, column 3240, which in the minified file - https://cdn.jsdelivr.net/npm/vega-embed@6/build-es5/vega-embed.min.js - is the spread operator in this code:

/\bsemver\b/i.test(process.env.NODE_DEBUG)?(...e)=>console.error("SEMVER",...e):()=>{},G=function(

Or in the non-minified file - https://cdn.jsdelivr.net/npm/vega-embed@6.17.0/build-es5/vega-embed.js - looks like the code is this:

 const debug = (
    typeof process === 'object' &&
    process.env &&
    process.env.NODE_DEBUG &&
    /\bsemver\b/i.test(process.env.NODE_DEBUG)
  ) ? (...args) => console.error('SEMVER', ...args)
    : () => {};

Is some 3rd party code not being transpiled?

[domoritz]

We shouldn't even need any code to check for node. Can you help fix this?

[pydolan]

I haven't used rollup.js before, but after looking at the vega project's rollup, I wonder if the babel plugin would help here: https://github.com/vega/vega/blob/master/rollup.config.js

[domoritz]

The es5 build is actually defaults from browserlist, which corresponds to https://browserslist.dev/?q=ZGVmYXVsdHM%3D, which should not support spread syntax today: https://caniuse.com/?search=spread. We use https://github.com/wessberg/rollup-plugin-ts so I guess the error might be there.

I will remove es5 bundles in the next release anyway so I won't have the cycles to investigate this further. Do you have time to fix this issue?

[pydolan]

Understandable about dropping the ES5 support. I'll see what I can do about resolving this issue.

I played around with it a bit, and I think the project's babel.config.js is being used behind the scenes by rollup (of course, it could be ignorance on my part about how this works).

I tried adding this to the ts() config, but then I ran into the "deoptimizePath" issue you posted about on here:

    transpiler: "babel",
    babelConfig: {"presets": ["@babel/preset-env"], "targets": "defaults"},

[domoritz]

Ohhh, that would make sense. We need the babel config for jest so we should ignore that for the build.

To fix rollup/rollup#4067, you can use an older version of rollup. Feel free to pin to a previous version for now.

[domoritz]

Fixed in #689