Error when using rollup's plugin terser

[xiki808]

I have the following error on the browser only when I build my project with rollup and including terser. Not sure what to do about it, I would like to keep using terser as it reduce the JS bundle from ~550kb to ~350kb.

Here is my rollup configuration:

import summary from 'rollup-plugin-summary'
import { terser } from 'rollup-plugin-terser'
import resolve from '@rollup/plugin-node-resolve'
import replace from '@rollup/plugin-replace'
import json from '@rollup/plugin-json'
import litSass from '@ponday/rollup-plugin-lit-sass'
import commonjs from '@rollup/plugin-commonjs'
import includePaths from 'rollup-plugin-includepaths'

export default {
  input: 'src/init-main.js',
  output: {
    file: 'init-main.js',
    format: 'esm'
  },
  onwarn (warning) {
    if (warning.code !== 'THIS_IS_UNDEFINED') {
      console.error(`(!) ${warning.message}`)
    }
  },
  plugins: [
    replace({
      preventAssignment: true,
      'Reflect.decorate': 'undefined',
      'process.env.NODE_ENV': JSON.stringify('production')
    }),
    resolve(),
    terser({
      ecma: 2017,
      module: true,
      warnings: true,
      mangle: {
        properties: {
          regex: /^__/
        }
      }
    }),
    summary(),
    json(),
    litSass(),
    commonjs(),
    includePaths({
      paths: ['src', 'src/components', 'src/styles']
    })
  ]
}

This is the error I get only when using terser: