Function isImported

packages/schematics/angular/utility/ast-utils.ts:547–570

(
  source: ts.SourceFile,
  classifiedName: string,
  importPath: string,
)

 * Determine if an import already exists.
 */
export function isImported(
  source: ts.SourceFile,
  classifiedName: string,
  importPath: string,
): boolean {
  const allNodes = getSourceNodes(source);
  const matchingNodes = allNodes
    .filter(ts.isImportDeclaration)
    .filter(
      (imp) => ts.isStringLiteral(imp.moduleSpecifier) && imp.moduleSpecifier.text === importPath,
    )
    .filter((imp) => {
      if (!imp.importClause) {
        return false;
      }
      const nodes = findNodes(imp.importClause, ts.isImportSpecifier).filter(
        (n) => n.getText() === classifiedName,
      );

      return nodes.length > 0;
    });

  return matchingNodes.length > 0;
}

/**
 * Returns the RouterModule declaration from NgModule metadata, if any.