Possible transpillation issue 83/101 versions

[dantaeusb]

Building poppperjs library (particularly this code https://github.com/floating-ui/floating-ui/blob/master/packages/dom/src/platform/getClippingRect.ts) with SWC 1.3.83 (left) and 1.3.101 (right)

On the left, a is first initialized, then reduced.
On the right, a is initialized inside the accumulator of a.reduce, which causes "Cannot read properties of undefined (reading 'reduce')"

I'm not entirely sure that it's caused by the SWC, but the code does change if I rollback to 83. Cannot yet create a minimal reproducible repo but seems serious enough to raise this question.

I'm going to catch some sleep to make sure I'm in a sane state, but looks like the code on the left cannot ever be run successfully, as a is not defined, and while reduce is called before a initialized in argument, it cannot work that way?

[kdy1]

I think it's a regression and it's a bug. Are you using swc minifier?

[dantaeusb]

Yep, with the following options:

  optimization: {
    minimize: true,
    minimizer: [
      new TerserPlugin({
        minify: TerserPlugin.swcMinify,
        terserOptions: {
          mangle: true,
        },
      }),
    ],
  },

[kdy1]

Can you file an issue?