Tapper

Pub Version Dart Package Docs License: MIT Build Status

Provides extension methods on all types to allow

  • inspection/mutation (tap),
  • transformation (pipe)
  • null chaining deconstruction (zip)
  • safe type conversion without casting (conv).

Tap

The Tap extension allows you to perform an operation on an object and then return the original object. It's useful for debugging, performing side effects, or logging.


int number = 10;
number = number
          .tap((n) => ++n )
          .tap((n) => print("The number is ${n}"));
// Prints: The number is 10

Pipe

The Pipe extension lets you transform an object.

int number = 10;
number = number
          .pipe((n) => ++n )
          .pipe((n) { 
            print("The number is ${n}"); 
            return n;
          });
// Prints: The number is 11

Zip

zip is an extension method for values and records that pulls any inner nullable values into the outer scope. This can be combined with the ? operator for more concise statements.

String? getName() => ...;
String? getPreferences() => ...;
String? getDetails() => ...;

if (getName()?
      .pipe((e) => e.zip(getPreferences()))?
      .pipe((e) => e.zip(getDetails()))
      case (String name, String preferences, String details)) {
  print("Hello $name, your preferences are $preferences and details are $details");
} else {
  return;
}
// vs
String? name = getName();
if (name == null) {
  return;
}
String? preferences = getPreferences();
if (preferences == null) {
  return;
}
String? details = getDetails();
if (details == null) {
  return;
}
print("Hello $name, your preferences are $preferences and details are $details");

Conv

The Conv extension is used for type conversion. You can convert an object from one type to another, handling cases where the conversion is not possible.


String numericString = "123";
int? number = numericString.convInt(); // convInt exists for this type
// number is now 123

Try Conv exists for dynamic inputs and concrete output.

Object nonNumericString = "abc";
Result<int, ConvException> numberResult = nonNumericString.tryConv<int>();
// conversion is not possible and handled with Result

List<Set<List<int>>> nestedInt = [{[1]}];
Result<double, ConvException> doubleResult = nestedInt.tryConv<double>();
// doubleResult is Ok(1.0)

Valid Conversions

Built-In

From Type To Type Method Used
int double convDouble()
int num convNum()
int BigInt convBigInt()
int String convString()
int bool convBool()
double int convInt()
double num convNum()
double BigInt convBigInt()
double String convString()
double bool convBool()
num int convInt()
num double convDouble()
num BigInt convBigInt()
num String convString()
num bool convBool()
BigInt int convInt()
BigInt double convDouble()
BigInt num convNum()
BigInt String convString()
BigInt bool convBool()
bool int convInt()
bool double convDouble()
bool num convNum()
bool BigInt convBigInt()
bool String convString()
String int? convInt()
String double? convDouble()
String num? convNum()
String BigInt? convBigInt()
String bool convBool()

Try Valid Conversions

Where T is any type in the current column.

From Types
int
double
num
BigInt
bool
String
Iterable<T>
To Types
int
double
num
BigInt
bool
String

Libraries

tapper