wrike/memoize_dart

Memoize

memoize returns cached result of function call when inputs were not changed from previous invocation.

Warning

memoize_dart now supports dart 2.12.0 and null safety since 3.0.0 version.

For 2.0.0 we drop func as dependency. Because it archived and doesn't support dart2.

If you need dart-1.24.3 use 1.4.0 version

Examples

memo1, memo2, ... memo10 compare arguments with == operator:

import 'dart:math';
import 'package:memoize/memoize.dart';

void main() {
  var rect1 = new Rectangle<int>(0, 0, 10, 10);
  var rect2 = new Rectangle<int>(0, 0, 10, 10);

  var func = memo1((Rectangle<int> a) => a.width * a.height);

  print(func(rect1));
  print(func(rect2)); // cached result is returned
}

imemo1, imemo2, ... imemo10 compare arguments with identical function:

import 'dart:math';
import 'package:memoize/memoize.dart';

void main() {
  var rect1 = new Rectangle<int>(0, 0, 10, 10);
  var rect2 = new Rectangle<int>(0, 0, 10, 10);

  var func = imemo1((Rectangle<int> a) => a.width * a.height);

  print(func(rect1));
  print(func(rect1)); // cached - same object instance
  print(func(rect2)); // not cached - different object instance
}

memo0 caches result on first call and can be used as lazy cache:

import 'dart:math';
import 'package:memoize/memoize.dart';

void main() {
  var func = memo0(() => new Rectangle<int>(0, 0, 10, 10));

  print(func());
  print(func()); // cached - same object instance
}

Contributors

• Brian Egan