#dart_ext A set of useful helper functions

##Installing

###1. Depend on it Add this to your package's pubspec.yaml file:

  dependencies:
    dart_ext: any

###2. Install it

  run pub get in Dart Editor or form command line

###3. Import it Add this line in your dart code:

  import 'package:dart_ext/dart_ext.dart';

##API

###Object ####dynamic clone(dynamic source) return a clone of the specified object

###Function ####relaxFn(Function function) An funtion wrapper which support flexable number of arguments

####bind(Function functoin, List args) Partially apply a function by filling in 0 to 5 number of its arguments;

• function - The function with partially filled args
• args - A List of prefilled args.

Example:

    Function add = (num a, num b) { return a + b; };
    var add5 = new bind(add, [5]);
    num rt = add5(6);

####invokeMethod(var target, String methodName, [arg0, arg1, arg2, arg3, arg4, arg5]) Invoke the given method in the target object.

• target - the object where the mehtod invoked from
• 'methodName` - the function name
• [arg0, arg1, arg2, arg3, arg4, arg5] - optional arguments. Suport 0 to 6 args. Exception: if the method didn't exist in the target object, it throws

###String ####String capitalize(String s) return a capitalized string

###Map ####dynamic getValue(Map source, dynamic key, [defaultValue = null]) return the value of given key in the map. If the key didn't exit, return given defaultValue or null if defaultValue didn't represent.

• source - the map to get value from
• key - the key of the value to get
• defaultValue - the defaultValue to return if the key didn't exist in the map. defaultValue can be a function.

Example:

    Map m = {
      'one': 1,
      'two': 2
    }
    
    num two = getValue(m, 'two');       //  two = 2
    num zero = getValue(m, 'zero');     //  zero = null
    zero = getValue(m, 'zero', 0);      //  zero = 0
    num four = getValue(m, 'three', (){ return getValue(m, 'three', 3) + 1; });  // four = 4

####void setValue(Map source, dynamic key, dynamic value) Add key/value to the given map. Equivalent to source[key] = value. It is convenient to use in a setter which set a value in map.

  Map _config = {};
  
  void set name(String value) => setValue(_config, 'name', value);

####Map merge(Map map1, others, {Function iterableMergeFunc}) Merge maps into a new map.

• others - can be a Map or a list
• iterableMergeFunc - a custom merge function to override default iterable merge behavior

  import 'package:dart_ext/collection_ext.dart';  // only import collection extension
  
  Map one = {
    'a': 'a',
    'b': 'b',
    'list': [{ 'one': 1 }, { 'two': 2 }]
  }
  
  Map two = {
    'a': 'A'
    'b': 3,
    'list': [{ 'two': 2 }, { 'three': 3 }, 4 ]
  }
  
  Map three = {
    'a': 'A',
    'b': 4,
    'list': [{ 'three': 3 }, { 'four': 4}, 5, 6]
  }
  
  Map merged = merge(one, two);
  // merged is:
  {
    'a': 'A',
    'b': 3,
    'list': [{'one': 1, 'two': 2}, {'two': 2, 'three': 3}, 4]
  }
  
  merged = merge(one, [two, three]);
  // merged is:
  {
    'a': 'A',
    'b': 4,
    'list': [{'one': 1, 'two': 2, 'three': 3}, {'two': 2, 'three': 3, 'four': 4}, 5, 6]
  }
  
  merged = merge(one, two, (target, other) {
    list<num> toReturn = [];
    
    void _merge(List l) {
        target.forEach((t) {
            if (t is Map) {
                t.forEach((k, v) {
                    if (toReturn.contains(v) == false) {
                        toReturn.add(v);
                    }
                });
            } else if (toReturn.contains(v) == false) {
                toReturn.add(v);
            }
        });
    }
    
    _merge(target);
    _merge(orther);
    return toReturn;
  });
  // merged is:
  {
    'a': 'A',
    'b': 3,
    'list': [1, 2, 3, 4]
  }

#####Note:

1. merge didn't check value type.
2. if the value was a Iterable, it merge items at the same index.