angular forEach方法遍历源码解读

functionforEach(obj, iterator, context) {

 varkey, length;

 if(obj) {

  if(isFunction(obj)) {

   for(keyinobj) {

    // Need to check if hasOwnProperty exists,

    // as on IE8 the result of querySelectorAll is an object without a hasOwnProperty function

    if(key !='prototype'&& key !='length'&& key !='name'&& (!obj.hasOwnProperty || obj.hasOwnProperty(key))) {

     iterator.call(context, obj[key], key, obj);

    }

   }

  }elseif(isArray(obj) || isArrayLike(obj)) {

   varisPrimitive =typeofobj !=='object'

   for(key = 0, length = obj.length; key < length; key++) {

    if(isPrimitive || keyinobj) {

     iterator.call(context, obj[key], key, obj);

    }

   }

  }elseif(obj.forEach && obj.forEach !== forEach) {

    obj.forEach(iterator, context, obj);

  }elseif(isBlankObject(obj)) {

   // createMap() fast path --- Safe to avoid hasOwnProperty check because prototype chain is empty

   for(keyinobj) {

    iterator.call(context, obj[key], key, obj);

   }

  }elseif(typeofobj.hasOwnProperty ==='function') {

   // Slow path for objects inheriting Object.prototype, hasOwnProperty check needed

   for(keyinobj) {

    if(obj.hasOwnProperty(key)) {

     iterator.call(context, obj[key], key, obj);

    }

   }

  }else{

   // Slow path for objects which do not have a method `hasOwnProperty`

   for(keyinobj) {

    if(hasOwnProperty.call(obj, key)) {

     iterator.call(context, obj[key], key, obj);

    }

   }

  }

 }

 returnobj;

}

varvalues = {name:'misko', gender:'male'};

varlog = [];

angular.forEach(values,function(value, key) {

 this.push(key +': '+ value);

}, log);