2.1.0 - Mar 07, 2026

https://pub.dev/packages/dart_either/versions/2.1.0

• Promoted Either.parSequenceN and Either.parTraverseN from experimental to stable.
• Added complete API docs and examples for Either.parSequenceN and Either.parTraverseN.
• Added unit tests for Either.parSequenceN and Either.parTraverseN, including concurrency-limit and short-circuit cases.
• Added @useResult annotations to public APIs that should not be ignored (for example: isLeft, isRight, map, flatMap, swap, exists, all, toEitherStream, left, right, and others).

API migration notes

• Either.parSequenceN changed from positional parameters to named parameters:

  // Before (2.0.0)
  Either.parSequenceN<String, int>(functions, n);
  
  // Now (2.1.0)
  Either.parSequenceN<String, int>(
    functions: functions,
    maxConcurrent: n,
  );

• Either.parTraverseN changed from positional parameters to named parameters:

  // Before (2.0.0)
  Either.parTraverseN<String, int, int>(values, mapper, n);
  
  // Now (2.1.0)
  Either.parTraverseN<String, int, int>(
    values: values,
    mapper: mapper,
    maxConcurrent: n,
  );

• maxConcurrent controls concurrency.
  • Pass a number (for example 2) to limit concurrency.
  • Pass null for unlimited concurrency.