angular/angular · error · FatalDiagnosticError

LOCAL_COMPILATION_UNRESOLVED_CONST

LOCAL_COMPILATION_UNRESOLVED_CONST

Error message

Unresolved identifier found for @Component.styles field! Did you import this identifier from a file outside of the compilation unit? This is not allowed when Angular compiler runs in local mode. Possible solutions: 1) Move the declarations into a file within the compilation unit, 2) Inline the styles, 3) Move the styles into separate files and include it using @Component.styleUrls

What it means

Thrown only when angularCompilerOptions.compilationMode is 'local' and the @Component.styles field evaluates to a DynamicValue produced by an unknown identifier. In local mode ngtsc compiles each compilation unit without the full program, so style constants imported from other files cannot be evaluated; the check scans the styles array (or single value) for DynamicValue.isFromUnknownIdentifier() and reports LOCAL_COMPILATION_UNRESOLVED_CONST on that identifier. The message itself lists the supported workarounds.

Source

Thrown at packages/compiler-cli/src/ngtsc/annotations/directive/src/shared.ts:900

  }

  const evaluated = evaluator.evaluate(expression);
  const value = typeof evaluated === 'string' ? [evaluated] : evaluated;

  // Check if the identifier used for @Component.styles cannot be resolved in local compilation
  // mode. if the case, an error specific to this situation is generated.
  if (compilationMode === CompilationMode.LOCAL) {
    let unresolvedNode: ts.Node | null = null;
    if (Array.isArray(value)) {
      const entry = value.find((e) => e instanceof DynamicValue && e.isFromUnknownIdentifier()) as
        DynamicValue | undefined;
      unresolvedNode = entry?.node ?? null;
    } else if (value instanceof DynamicValue && value.isFromUnknownIdentifier()) {
      unresolvedNode = value.node;
    }

    if (unresolvedNode !== null) {
      throw new FatalDiagnosticError(
        ErrorCode.LOCAL_COMPILATION_UNRESOLVED_CONST,
        unresolvedNode,
        'Unresolved identifier found for @Component.styles field! Did you import ' +
          'this identifier from a file outside of the compilation unit? This is ' +
          'not allowed when Angular compiler runs in local mode. Possible ' +
          'solutions: 1) Move the declarations into a file within the compilation ' +
          'unit, 2) Inline the styles, 3) Move the styles into separate files and ' +
          'include it using @Component.styleUrls',
      );
    }
  }

  if (!isStringArrayOrDie(value, 'styles', expression)) {
    throw createValueHasWrongTypeError(
      expression,
      value,
      `Failed to resolve @Component.styles to a string or an array of strings`,
    );

View on GitHub (pinned to 51cb07e980)

Solutions

1. Inline the styles into the decorator: `styles: ['.panel { color: red; }']`.
2. Move the styles into their own file and load via `styleUrls: ['./comp.css']` (or `styleUrl` for a single file).
3. Move the style constant's declaration into the same compilation unit (the same file) so it can be evaluated.
4. If none are workable, opt back to full compilation: set `"compilationMode": "full"` in angularCompilerOptions.

Example fix

// before
// styles.ts
export const PANEL_STYLES = ['.panel { color: red; }'];
// comp.ts
import {PANEL_STYLES} from './styles';
@Component({selector: 'app-panel', template: '', styles: [PANEL_STYLES]})

// after
@Component({selector: 'app-panel', template: '', styles: ['.panel { color: red; }']})
// or
@Component({selector: 'app-panel', template: '', styleUrl: './panel.css'})

// before enabling local compilation, scan for imported style constants
const re = /styles\s*:\s*\[?\s*([A-Za-z_$][\w$]*)/g;
for (const m of src.matchAll(re)) {
  const ident = m[1];
  if (new RegExp(`import[^;]*\\b${ident}\\b`).test(src)) {
    throw new Error(`${ident} is imported — styles must be inline or use styleUrls in local mode`);
  }
}

When it happens

Trigger: `import {STYLES} from './styles';` with `@Component({styles: [STYLES]})` while tsconfig sets `"angularCompilerOptions": {"compilationMode": "local"}`; also `styles: [THEMES.panel]` with an imported THEMES object.

Common situations: Enabling local compilation mode for faster builds in codebases that share style constants across files; monorepos with central style/token modules; libraries migrating Angular versions where local mode restrictions first apply.

Related errors

• VALUE_HAS_WRONG_TYPE
• COMPONENT_INVALID_STYLE_URLS
• DECORATOR_COLLISION
• DECORATOR_UNEXPECTED
• INITIALIZER_API_WITH_DISALLOWED_DECORATOR

AI-assisted analysis of angular/angular@51cb07e980 (2026-08-22). Data as JSON: /api/errors/3e6f40656149a547. Report an issue: GitHub.