v0.21.0

⚠️ Breaking Changes:

• TypeScript v3.1 and v3.2 is no longer officially supported
• Node.js v6 is no longer supported
• Rule.supports can now return a string respresenting the reason for not supporting the file
• Linter#lintAndFix now requires a ProgramFactory instead of Program
• Linter#lintAndFix UpdateFileCallback is now expected to only return a SourceFile
• no-inferred-empty-object was renamed to no-uninferred-type-parameter

Features:

• rules now debuglog the reason for not supporting a certain file
• performance improvements
  • when linting with --project --references
    • parsed tsconfig.json files are cached for all project references
  • when linting with --project --fix
    • the project's dependency graph is recalculated lazily the next time a typed rule reuqests type information after fixing a file
    • module resolutions are cached between fixes
• no-uninferred-type-parameter properly handles new default constraint unknown
• no-uninferred-type-parameter now detects uninferred type parameters in JS code falling back to any
• no-uninferred-type-parameter correctly handles higher order function types
• no-useless-initializer checks array destructuring
• better handling of computed property names
• better handling of object and array destructuring assignments

Bugfixes:

• comments are now included in the transpiled code and declaration files, this makes JSDoc and deprecations visible to API consumers