Diagnostic Filtering

Source: src/core/filter-diagnostics.ts

What

Removes diagnostics that match the user's ignore configuration after all rules have run.

Why

Users may want to suppress known issues or exclude generated files from results without disabling the rule entirely. For example, you might want no-orm-in-services to run everywhere except in your legacy module.

Input

diagnostics: Diagnostic[]          // all diagnostics from rule execution
config: NestjsDoctorConfig         // contains ignore.rules and ignore.files

Output

Diagnostic[]    // filtered array (subset of input)

How It Works

Two filtering mechanisms:

Rule Ignoring

ignore.rules contains rule IDs to suppress:

{
  "ignore": {
    "rules": ["architecture/no-orm-in-services"]
  }
}

Exact match against the diagnostic's rule field. All diagnostics from that rule are removed.

File Ignoring

ignore.files contains glob patterns for files whose diagnostics should be hidden:

{
  "ignore": {
    "files": ["src/generated/**", "src/legacy/**"]
  }
}

File paths are normalized to forward slashes before matching, so patterns work across platforms.

Performance

If no ignore config is set (the default), the filter returns the original array immediately without iterating.

Difference from rules Config

• config.rules disables a rule entirely — it never runs
• config.ignore.rules lets the rule run but hides its output

This distinction matters for project-scoped rules that cross-reference data. For example, no-missing-injectable checks providers against the module graph. Disabling it with config.rules means the rule will not run at all. Ignoring it with config.ignore.rules means the rule runs (maintaining data consistency) but its diagnostics are hidden.

Debugging Tips

• If diagnostics are disappearing unexpectedly, check ignore.rules and ignore.files in your config.
• File patterns use glob syntax via picomatch. Double-star ** matches any depth.