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avoid-future-tostring

added in: 1.6.0
warning
Pro+
preset: recommended

Warns when a Future is the target of the toString method or is used in an interpolation.

The result of calling toString() on a Future is Instance of '_Future<String>' and is usually not expected.

Example​

❌ Bad:

void main() {
  final myFuture = Future.value(1);

  // LINT: Avoid calling 'toString' on 'Futures'. Try awaiting the value before calling 'toString'.
  print(myFuture.toString());
  
  // LINT: Avoid calling 'toString' on 'Futures'. Try awaiting the value before calling 'toString'.
  print('hello $myFuture');
}

✅ Good:

Future<void> withAwait() async {
  final myFuture = Future.value(1);

  print((await myFuture).toString()); // Correct, awaited
  print('hello ${(await myFuture)}'); // Correct, awaited
}

Additional Resources​