Plugin very slow when using with other preset

[mathieumure]

Hi,

I notice performances issues when using this plugin with other eslint config preset such as eslint-config-airbnb-base.

For instance, I got 7 svelte files and it tooks 11seconds to lint with 'airbnb-base' active and only 1s when I removed it.

Here is my .eslintrc file :

module.exports = {
  env: {
    browser: true,
    es2021: true,
  },
  extends: ['airbnb-base', 'prettier'],
  ignorePatterns: ['public/build'],
  parser: '@typescript-eslint/parser',
  parserOptions: {
    ecmaVersion: 2019,
    sourceType: 'module',
  },
  plugins: ['svelte3', '@typescript-eslint'],
  overrides: [
    {
      files: ['*.svelte'],
      processor: 'svelte3/svelte3',
      rules: {
        'import/first': ['off'],
        'import/no-duplicates': ['off'],
        'import/no-mutable-exports': ['off'],
      },
    },
    {
      files: ['.eslintrc.js', '.prettierrc.js'],
      rules: {
        'global-require': ['off'],
        'import/no-extraneous-dependencies': ['off'],
      },
    },
  ],
  settings: {
    'svelte3/typescript': require('typescript'),
  },
  rules: {},
};

Can you take a look ? Thanks 🙏

[clintwood]

Hi, I began having the same issue the moment I switched to using svelte-preprocess and type="ts" for svelte files. I am also using airbnb-base but not prettier. From what I can see this is because airbnb-base includes import/* rules which are very useful. Prior to using a preprocess config linting would take about 2-3 seconds. Now it takes 3 minutes. Here are the timings for my lint with preprocessing (which only includes TS preprocessing)

I'm not convinced your PR #93 will make much difference. I think to resolve this there needs to be some caching strategy for import/* rules because it looks like it is literally compiling each import for each svelte file for each rule check.

[Conduitry]

This should be fixed in 3.2.0 by way of #93, which lets you specify that the compiler be lazily loaded.