core-js/src/dict.js

Standard library

!function(DICT){
  function Dict(iterable){
    var dict = create(null);
    if(iterable != undefined){
      if(isIterable(iterable)){
        for(var iter = getIterator(iterable), step, value; !(step = iter.next()).done;){
          value = step.value;
          dict[value[0]] = value[1];
        }
      } else assign(dict, iterable);
    }
    return dict;
  }
  Dict[PROTOTYPE] = null;
  
  function DictIterator(iterated, kind){
    set(this, ITER, {o: ES5Object(iterated), a: getKeys(iterated), i: 0, k: kind});
  }
  createIterator(DictIterator, DICT, function(){
    var iter   = this[ITER]
      , index  = iter.i++
      , keys   = iter.a
      , kind   = iter.k
      , key, value;
    if(index >= keys.length)return iterResult(1);
    key = keys[index];
    if(kind == KEY)       value = key;
    else if(kind == VALUE)value = iter.o[key];
    else                  value = [key, iter.o[key]];
    return iterResult(0, value);
  });
  function createDictIter(kind){
    return function(it){
      return new DictIterator(it, kind);
    }
  }
  
  /*
   * 0 -> forEach
   * 1 -> map
   * 2 -> filter
   * 3 -> some
   * 4 -> every
   * 5 -> find
   * 6 -> findKey
   * 7 -> mapPairs
   */
  function createDictMethod(type){
    var isMap    = type == 1
      , isEvery  = type == 4;
    return function(object, callbackfn, that /* = undefined */){
      var f      = ctx(callbackfn, that, 3)
        , O      = ES5Object(object)
        , keys   = getKeys(O)
        , length = keys.length
        , i      = 0
        , result = isMap || type == 7 || type == 2 ? new (generic(this, Dict)) : undefined
        , key, val, res;
      while(length > i){
        key = keys[i++];
        val = O[key];
        res = f(val, key, object);
        if(type){
          if(isMap)result[key] = res;             // map
          else if(res)switch(type){
            case 2: result[key] = val; break      // filter
            case 3: return true;                  // some
            case 5: return val;                   // find
            case 6: return key;                   // findKey
            case 7: result[res[0]] = res[1];      // mapPairs
          } else if(isEvery)return false;         // every
        }
      }
      return type == 3 || isEvery ? isEvery : result;
    }
  }
  function createDictReduce(isTurn){
    return function(object, mapfn, init){
      assertFunction(mapfn);
      var O      = ES5Object(object)
        , keys   = getKeys(O)
        , length = keys.length
        , i      = 0
        , memo, key, result;
      if(isTurn)memo = init == undefined ? new (generic(this, Dict)) : Object(init);
      else if(arguments.length < 3){
        assert(length, REDUCE_ERROR);
        memo = O[keys[i++]];
      } else memo = Object(init);
      while(length > i){
        result = mapfn(memo, O[key = keys[i++]], key, object);
        if(isTurn){
          if(result === false)break;
        } else memo = result;
      }
      return memo;
    }
  }
  var findKey = createDictMethod(6);
  function includes(object, el){
    return (el == el ? keyOf(object, el) : findKey(object, sameNaN)) !== undefined;
  }
  
  var dictMethods = {
    keys:    createDictIter(KEY),
    values:  createDictIter(VALUE),
    entries: createDictIter(KEY+VALUE),
    forEach: createDictMethod(0),
    map:     createDictMethod(1),
    filter:  createDictMethod(2),
    some:    createDictMethod(3),
    every:   createDictMethod(4),
    find:    createDictMethod(5),
    findKey: findKey,
    mapPairs:createDictMethod(7),
    reduce:  createDictReduce(false),
    turn:    createDictReduce(true),
    keyOf:   keyOf,
    includes:includes,
    // Has / get / set own property
    has: has,
    get: function(object, key){
      if(has(object, key))return object[key];
    },
    set: createDefiner(0),
    isDict: function(it){
      return isObject(it) && getPrototypeOf(it) === Dict[PROTOTYPE];
    }
  };
  
  if(REFERENCE_GET)for(var key in dictMethods)!function(fn){
    function method(){
      for(var args = [this], i = 0; i < arguments.length;)args.push(arguments[i++]);
      return invoke(fn, args);
    }
    fn[REFERENCE_GET] = function(){
      return method;
    }
  }(dictMethods[key]);
  
  $define(GLOBAL + FORCED, {Dict: assignHidden(Dict, dictMethods)});
}('Dict');