Performance difference when using different parserOptions on with-typescript

[freakzlike]

Hi,
I'm migrating one of my projects to a fresh create-vue. I have notice a big performance difference when using @vue/eslint-config-standard-with-typescript and following config changes of parserOptions:

  overrides: [
    {
      files: [
        '**/*.ts',
        '**/*.vue'
      ],
      extends: [
        '@vue/eslint-config-standard-with-typescript'
      ],
      parser: 'vue-eslint-parser',
      parserOptions: {
        tsconfigRootDir: __dirname,
        parser: {
          '<template>': 'espree',
          js: '@typescript-eslint/parser',
          ts: '@typescript-eslint/parser'
        },
        project: ['./tsconfig.json']
      }
    }
  ]

Performance test:

• With the parserOptions: 47s
• Without the parserOptions: 98s

My eslint run was twice as fast. Not sure if this is suitable for everyone.

Edit

What could be also interesting Glob pattern in parser's option "project" slows down linting (typescript-eslint/typescript-eslint#2611)

[haoqunjiang]

Thanks for the issue.

I think the perf difference mostly comes from '<template>': 'espree'. In the latest version of this package, it needs to be used together with @vue/eslint-config-typescript, and I added a tsSyntaxInTemplates option there. And luckily, the project option is no longer needed in the latest typescript-eslint versions. Hopefully these changes have helped fix the performance issue in this package.