memoize function

Function memoize(Function func)

Returns a memoized version of func.

The function result is cached based on its arguments. Subsequent calls with the same arguments return the cached result.

Example:

int compute(int x) {
  print('Computing...');
  return x * x;
}

var memoizedCompute = memoize(compute);
memoizedCompute(2); // Prints 'Computing...' and returns 4
memoizedCompute(2); // Returns 4 without printing

Implementation

Function memoize(Function func) {
  final cache = HashMap<List<dynamic>, dynamic>(
    equals: (a, b) => a.length == b.length && const ListEquality<dynamic>().equals(a, b),
    hashCode: (key) => key.fold(0, (prev, element) => prev ^ element.hashCode),
  );

  return (List<dynamic> args) {
    if (cache.containsKey(args)) {
      return cache[args];
    } else {
      final result = Function.apply(func, args);
      cache[args] = result;
      return result;
    }
  };
}