js深入研究之扩展类，克隆对象，混合类（自定义的extend函数，clone函数，与augment函数）

1.类扩展

/* EditInPlaceField类 */
/* 扩展函数 */ 
function extend(subClass, superClass) {
  var F = function() {};
  F.prototype = superClass.prototype;
  subClass.prototype = new F();
  subClass.prototype.constructor = subClass;

  subClass.superclass = superClass.prototype;
  if(superClass.prototype.constructor == Object.prototype.constructor) {
    superClass.prototype.constructor = superClass;
  }
}


function EditInPlaceField(id, parent, value) { // 构造函数
  this.id = id;
  this.value = value || 'default value';
  this.parentElement = parent;

  this.createElements(this.id);
  this.attachEvents();
};

EditInPlaceField.prototype = {
  createElements: function(id) {
    this.containerElement = document.createElement('div');
    this.parentElement.appendChild(this.containerElement);

    this.staticElement = document.createElement('span');
    this.containerElement.appendChild(this.staticElement);
    this.staticElement.innerHTML = this.value;
    
    this.fieldElement = document.createElement('input');
    this.fieldElement.type = 'text';
    this.fieldElement.value = this.value;
    this.containerElement.appendChild(this.fieldElement);
    
    this.saveButton = document.createElement('input');
    this.saveButton.type = 'button';
    this.saveButton.value = 'Save';
    this.containerElement.appendChild(this.saveButton);    

    this.cancelButton = document.createElement('input');
    this.cancelButton.type = 'button';
    this.cancelButton.value = 'Cancel';
    this.containerElement.appendChild(this.cancelButton);    
        
    this.convertToText();
  },
  attachEvents: function() {
    var that = this;
    addEvent(this.staticElement, 'click', function() { that.convertToEditable(); });
    addEvent(this.saveButton, 'click', function() { that.save(); });
    addEvent(this.cancelButton, 'click', function() { that.cancel(); });
  },
  
  convertToEditable: function() {
    this.staticElement.style.display = 'none';
    this.fieldElement.style.display = 'inline';
    this.saveButton.style.display = 'inline';
    this.cancelButton.style.display = 'inline';        

    this.setValue(this.value);
  },
  save: function() {
    this.value = this.getValue();
    var that = this;
    var callback = {
      success: function() { that.convertToText(); },
      failure: function() { alert('Error saving value.'); }
    };
    ajaxRequest('GET', 'save.php?id=' + this.id + '&value=' + this.value, callback);
  },
  cancel: function() {
    this.convertToText();
  },
  convertToText: function() {
    this.fieldElement.style.display = 'none';
    this.saveButton.style.display = 'none';
    this.cancelButton.style.display = 'none';     
    this.staticElement.style.display = 'inline';

    this.setValue(this.value);
  },
  
  setValue: function(value) {
    this.fieldElement.value = value;
    this.staticElement.innerHTML = value;
  },
  getValue: function() {
    return this.fieldElement.value;
  }
};

var titleClassical = new EditInPlaceField('titleClassical', $('doc'), 'Title Here');
var currentTitleText = titleClassical.getValue();

/* EditInPlaceArea类 */

function EditInPlaceArea(id, parent, value) {
  EditInPlaceArea.superclass.constructor.call(this, id, parent, value);
};
extend(EditInPlaceArea, EditInPlaceField);

// Override certain methods.

EditInPlaceArea.prototype.createElements = function(id) {
  this.containerElement = document.createElement('div');
  this.parentElement.appendChild(this.containerElement);

  this.staticElement = document.createElement('p');
  this.containerElement.appendChild(this.staticElement);
  this.staticElement.innerHTML = this.value;
  
  this.fieldElement = document.createElement('textarea');
  this.fieldElement.value = this.value;
  this.containerElement.appendChild(this.fieldElement);
  
  this.saveButton = document.createElement('input');
  this.saveButton.type = 'button';
  this.saveButton.value = 'Save';
  this.containerElement.appendChild(this.saveButton);

  this.cancelButton = document.createElement('input');
  this.cancelButton.type = 'button';
  this.cancelButton.value = 'Cancel';
  this.containerElement.appendChild(this.cancelButton);
      
  this.convertToText();
};
EditInPlaceArea.prototype.convertToEditable = function() {
  this.staticElement.style.display = 'none';
  this.fieldElement.style.display = 'block';
  this.saveButton.style.display = 'inline';
  this.cancelButton.style.display = 'inline';

  this.setValue(this.value);
};
EditInPlaceArea.prototype.convertToText = function() {
  this.fieldElement.style.display = 'none';
  this.saveButton.style.display = 'none';
  this.cancelButton.style.display = 'none';
  this.staticElement.style.display = 'block';

  this.setValue(this.value);
};

2.对象克隆

/* EditInPlaceField对象*/
/* 克隆函数 */
function clone(object) {
    function F() {}
    F.prototype = object;
    return new F;
}

var EditInPlaceField = {
  configure: function(id, parent, value) {
    this.id = id;
    this.value = value || 'default value';
    this.parentElement = parent;

    this.createElements(this.id);
    this.attachEvents();
  },
  createElements: function(id) {
    this.containerElement = document.createElement('div');
    this.parentElement.appendChild(this.containerElement);

    this.staticElement = document.createElement('span');
    this.containerElement.appendChild(this.staticElement);
    this.staticElement.innerHTML = this.value;
    
    this.fieldElement = document.createElement('input');
    this.fieldElement.type = 'text';
    this.fieldElement.value = this.value;
    this.containerElement.appendChild(this.fieldElement);
    
    this.saveButton = document.createElement('input');
    this.saveButton.type = 'button';
    this.saveButton.value = 'Save';
    this.containerElement.appendChild(this.saveButton);    

    this.cancelButton = document.createElement('input');
    this.cancelButton.type = 'button';
    this.cancelButton.value = 'Cancel';
    this.containerElement.appendChild(this.cancelButton);    
        
    this.convertToText();
  },
  attachEvents: function() {
    var that = this;
    addEvent(this.staticElement, 'click', function() { that.convertToEditable(); });
    addEvent(this.saveButton, 'click', function() { that.save(); });
    addEvent(this.cancelButton, 'click', function() { that.cancel(); });
  },
  
  convertToEditable: function() {
    this.staticElement.style.display = 'none';
    this.fieldElement.style.display = 'inline';
    this.saveButton.style.display = 'inline';
    this.cancelButton.style.display = 'inline';        

    this.setValue(this.value);
  },
  save: function() {
    this.value = this.getValue();
    var that = this;
    var callback = {
      success: function() { that.convertToText(); },
      failure: function() { alert('Error saving value.'); }
    };
    ajaxRequest('GET', 'save.php?id=' + this.id + '&value=' + this.value, callback);
  },
  cancel: function() {
    this.convertToText();
  },
  convertToText: function() {
    this.fieldElement.style.display = 'none';
    this.saveButton.style.display = 'none';
    this.cancelButton.style.display = 'none';     
    this.staticElement.style.display = 'inline';

    this.setValue(this.value);
  },
  
  setValue: function(value) {
    this.fieldElement.value = value;
    this.staticElement.innerHTML = value;
  },
  getValue: function() {
    return this.fieldElement.value;
  }
};

var titlePrototypal = clone(EditInPlaceField);
titlePrototypal.configure(' titlePrototypal ', $('doc'), 'Title Here');
var currentTitleText = titlePrototypal.getValue();

/* EditInPlaceArea对象*/

var EditInPlaceArea = clone(EditInPlaceField);

// Override certain methods.

EditInPlaceArea.createElements = function(id) {
  this.containerElement = document.createElement('div');
  this.parentElement.appendChild(this.containerElement);

  this.staticElement = document.createElement('p');
  this.containerElement.appendChild(this.staticElement);
  this.staticElement.innerHTML = this.value;
  
  this.fieldElement = document.createElement('textarea');
  this.fieldElement.value = this.value;
  this.containerElement.appendChild(this.fieldElement);
  
  this.saveButton = document.createElement('input');
  this.saveButton.type = 'button';
  this.saveButton.value = 'Save';
  this.containerElement.appendChild(this.saveButton);

  this.cancelButton = document.createElement('input');
  this.cancelButton.type = 'button';
  this.cancelButton.value = 'Cancel';
  this.containerElement.appendChild(this.cancelButton);
      
  this.convertToText();
};
EditInPlaceArea.convertToEditable = function() {
  this.staticElement.style.display = 'none';
  this.fieldElement.style.display = 'block';
  this.saveButton.style.display = 'inline';
  this.cancelButton.style.display = 'inline';

  this.setValue(this.value);
};
EditInPlaceArea.convertToText = function() {
  this.fieldElement.style.display = 'none';
  this.saveButton.style.display = 'none';
  this.cancelButton.style.display = 'none';     
  this.staticElement.style.display = 'block';

  this.setValue(this.value);
};

3.混合类

/* 混合类 */
/* 混合函数 */
function augment(receivingClass, givingClass) {
  for(methodName in givingClass.prototype) { 
    if(!receivingClass.prototype[methodName]) {
      receivingClass.prototype[methodName] = givingClass.prototype[methodName];
    }
  }
}

/* 改进的增加函数 */

function augment(receivingClass, givingClass) {
  if(arguments[2]) { // Only give certain methods.
    for(var i = 2, len = arguments.length; i < len; i++) {
      receivingClass.prototype[arguments[i]] = givingClass.prototype[arguments[i]];
    }
  } 
  else { // Give all methods.
    for(methodName in givingClass.prototype) { 
      if(!receivingClass.prototype[methodName]) {
        receivingClass.prototype[methodName] = givingClass.prototype[methodName];
      }
    }
  }
}

var EditInPlaceMixin = function() {};
EditInPlaceMixin.prototype = {
  createElements: function(id) {
    this.containerElement = document.createElement('div');
    this.parentElement.appendChild(this.containerElement);

    this.staticElement = document.createElement('span');
    this.containerElement.appendChild(this.staticElement);
    this.staticElement.innerHTML = this.value;
    
    this.fieldElement = document.createElement('input');
    this.fieldElement.type = 'text';
    this.fieldElement.value = this.value;
    this.containerElement.appendChild(this.fieldElement);
    
    this.saveButton = document.createElement('input');
    this.saveButton.type = 'button';
    this.saveButton.value = 'Save';
    this.containerElement.appendChild(this.saveButton);

    this.cancelButton = document.createElement('input');
    this.cancelButton.type = 'button';
    this.cancelButton.value = 'Cancel';
    this.containerElement.appendChild(this.cancelButton);
        
    this.convertToText();
  },
  attachEvents: function() {
    var that = this;
    addEvent(this.staticElement, 'click', function() { that.convertToEditable(); });
    addEvent(this.saveButton, 'click', function() { that.save(); });
    addEvent(this.cancelButton, 'click', function() { that.cancel(); });
  },
  
  convertToEditable: function() {
    this.staticElement.style.display = 'none';
    this.fieldElement.style.display = 'inline';
    this.saveButton.style.display = 'inline';
    this.cancelButton.style.display = 'inline';

    this.setValue(this.value);
  },
  save: function() {
    this.value = this.getValue();
    var that = this;
    var callback = {
      success: function() { that.convertToText(); },
      failure: function() { alert('Error saving value.'); }
    };
    ajaxRequest('GET', 'save.php?id=' + this.id + '&value=' + this.value, callback);
  },
  cancel: function() {
    this.convertToText();
  },
  convertToText: function() {
    this.fieldElement.style.display = 'none';
    this.saveButton.style.display = 'none';
    this.cancelButton.style.display = 'none';     
    this.staticElement.style.display = 'inline';

    this.setValue(this.value);
  },
  
  setValue: function(value) {
    this.fieldElement.value = value;
    this.staticElement.innerHTML = value;
  },
  getValue: function() {
    return this.fieldElement.value;
  }
};

/* EditInPlaceField class. */

function EditInPlaceField(id, parent, value) {
  this.id = id;
  this.value = value || 'default value';
  this.parentElement = parent;

  this.createElements(this.id);
  this.attachEvents();
};
augment(EditInPlaceField, EditInPlaceMixin);

/* EditInPlaceArea class. */

function EditInPlaceArea(id, parent, value) {
  this.id = id;
  this.value = value || 'default value';
  this.parentElement = parent;

  this.createElements(this.id);
  this.attachEvents();
};

// Add certain methods so that augment won't include them.

EditInPlaceArea.prototype.createElements = function(id) {
  this.containerElement = document.createElement('div');
  this.parentElement.appendChild(this.containerElement);

  this.staticElement = document.createElement('p');
  this.containerElement.appendChild(this.staticElement);
  this.staticElement.innerHTML = this.value;
  
  this.fieldElement = document.createElement('textarea');
  this.fieldElement.value = this.value;
  this.containerElement.appendChild(this.fieldElement);
  
  this.saveButton = document.createElement('input');
  this.saveButton.type = 'button';
  this.saveButton.value = 'Save';
  this.containerElement.appendChild(this.saveButton);

  this.cancelButton = document.createElement('input');
  this.cancelButton.type = 'button';
  this.cancelButton.value = 'Cancel';
  this.containerElement.appendChild(this.cancelButton);
      
  this.convertToText();
};
EditInPlaceArea.prototype.convertToEditable = function() {
  this.staticElement.style.display = 'none';
  this.fieldElement.style.display = 'block';
  this.saveButton.style.display = 'inline';
  this.cancelButton.style.display = 'inline';

  this.setValue(this.value);
};
EditInPlaceArea.prototype.convertToText = function() {
  this.fieldElement.style.display = 'none';
  this.saveButton.style.display = 'none';
  this.cancelButton.style.display = 'none';
  this.staticElement.style.display = 'block';

  this.setValue(this.value);
};

augment(EditInPlaceArea, EditInPlaceMixin);

点评：

js分为类和对象、函数。

其中又包含多种形式，属性，数组属性，函数，私有函数，公有函数，静态函数。

小的基础方法，可以有大的用途，比如extend方法，clone方法，还有augment方法。