Class constructor <FooBar> cannot be invoked without 'new'

[evdama]

After upgrading from 2.0.4 to 2.0.5 I'm getting this error on the dev console when I run my rollup config in my Svelte project:

> Class constructor SvelteExtractor cannot be invoked without 'new'
TypeError: Class constructor SvelteExtractor cannot be invoked without 'new'
    at extractSelectors (/Users/sa/0/edm/node_modules/purgecss/lib/purgecss.js:1:2358)
    at PurgeCSS.extractSelectorsFromFiles (/Users/sa/0/edm/node_modules/purgecss/lib/purgecss.js:1:5802)
    at async /Users/sa/0/edm/node_modules/@fullhuman/postcss-purgecss/lib/postcss-purgecss.js:1:501

In my rollup config I got SvelteExtractor which worked fine until today's upgrade
https://gist.github.com/evdama/253e7a78b0c3a2e6ec875963e6bdd339#file-rollup-config-js-L37

class SvelteExtractor {
  static extract(content) {
    const regExp = new RegExp(/[A-Za-z0-9-_:/]+/g)
    const matchedTokens = []
    let match = regExp.exec(content)

    while (match) {
      if (match[0].startsWith('class:')) {
        matchedTokens.push(match[0].substring(6))
      } else {
        matchedTokens.push(match[0])
      }
      match = regExp.exec(content)
    }
    return matchedTokens
  }
}

SvelteExtractor is used in line 74
https://gist.github.com/evdama/253e7a78b0c3a2e6ec875963e6bdd339#file-rollup-config-js-L74

const postcssPlugins = (purgecss = false) =>
  [
    require('postcss-import')(),
    require('postcss-url')(),
    require('tailwindcss')({ config: 'tailwind.config.js' }),
    require('autoprefixer')({
      overrideBrowserslist: 'last 1 version',
    }),
    // Do not purge the CSS in dev mode to be able to play with classes in the browser dev-tools.
    purgecss &&
      require('@fullhuman/postcss-purgecss')({
        content: [
          './src/**/*.html',
          './src/**/*.svelte',
          './src/**/*.css',
          './static/**/*.css',
        ],
        extractors: [
          {
            extractor: SvelteExtractor,      // <-- I suppose this is where the error occurs?

            // Specify the file extensions to include when scanning for
            // class names.
            extensions: ['svelte', 'css', 'html'],
          },
        ],
        fontFace: true,
        // Whitelist selectors to stop Purgecss from removing them from your CSS.
        whitelist: [ 'html', 'body' ],
        whitelistPatterns: [/svelte-/]
      }),
    purgecss &&
      require('cssnano')({
        preset: 'default',
      }),
  ].filter(Boolean)

If I change above line to extractor: new SvelteExtractor() the inital error goes away but is replaced by

> t is not a function
TypeError: t is not a function
    at extractSelectors (/Users/sa/0/edm/node_modules/purgecss/lib/purgecss.js:1:2358)
    at PurgeCSS.extractSelectorsFromFiles (/Users/sa/0/edm/node_modules/purgecss/lib/purgecss.js:1:5802)
    at async /Users/sa/0/edm/node_modules/@fullhuman/postcss-purgecss/lib/postcss-purgecss.js:1:501

[Ffloriel]

The class based extractor has been removed on version 2 in favor of a function.
It should work if you use the extract function by itself without a class.
PurgeCSS is complaining about the fact the extractor provided is not a function.

[evdama]

Ok, worked, moved to below function instead of former class

  const svelteExtractor = ( content ) => {
    const regExp = new RegExp(/[A-Za-z0-9-_:/]+/g)
    const matchedTokens = []
    let match = regExp.exec(content)

    while (match) {
      if (match[0].startsWith('class:')) {
        matchedTokens.push(match[0].substring(6))
      } else {
        matchedTokens.push(match[0])
      }
      match = regExp.exec(content)
    }
    return matchedTokens
  }

thanks! closing...