在JavaScript中调用父级方法

Question

我有一个JavaScript类，我想通过创建一个子类来重写父级方法。但是，我正在努力研究如何从父级上下文中调用子级方法。

这是我父母的精简版：

// "rules" is a global hash 

function ForumFilter() { 
    this.scanText = function(title, body) { 
     // Save 'this' context, as each() overwrites it 
     var that = this; 
     // This is jQuery each() 
     $.each(rules, function(ruleName, rule) { 
      // rule.search is a regex 
      var match = rule.search.test(body); 
      if (match) 
      { 
       that.isPassed = false; 
       // ** I'd like to call a child method here, 
       // ** but it only calls the method in this class 
       that.setRuleFailed(ruleName); 
      } 
     }); 
    } 

    this.setRuleFailed = function(ruleName) { 
     this.failedRules.push(ruleName); 
    } 
} 

这里是我的孩子尝试：

ForumFilterTest.prototype = new ForumFilter(); 
ForumFilterTest.prototype.setRuleFailed = function(ruleName) { 
    // Call parent 
    ForumFilter.setRuleFailed(ruleName); 
    // Record that this one has triggered 
    this.triggered.push(ruleName); 
} 

这里是我的呼唤从子实例我父类的方法：

var scanner = new ForumFilterTest(); 
scanner.scanText("Hello", "Hello"); 

因此，在scanText（它只存在于父项中）可能会调用setRuleFailed，它应该调用ForumFilterTest中的版本，该版本又调用它覆盖的类。因此，正如它的名字所暗示的那样，我试图向父级添加一个行为用于测试目的，所以当然我想要使用父级方法，如果ForumFilter是自己实例化的。

Answer 1

在更好地理解您的问题后，下面是我实际提出的更改。具体而言，您需要将您的ForumFilter方法移至其prototype。这将允许ForumFilterTest方法明确引用ForumFilter方法。

步骤1：将ForumFilter方法移至其prototype。

function ForumFilter() {} 
ForumFilter.prototype.scanText = function(title, body) { 
    // Save 'this' context, as each() overwrites it 
    var that = this; 
    // This is jQuery each() 
    $.each(rules, function(ruleName, rule) { 
     // rule.search is a regex 
     var match = rule.search.test(body); 
     if (match) 
     { 
      that.isPassed = false; 
      // ** I'd like to call a child method here, 
      // ** but it only calls the method in this class 
      that.setRuleFailed(ruleName); 
     } 
    }); 
}; 
ForumFilter.prototype.setRuleFailed = function(ruleName) { 
    this.failedRules.push(ruleName); 
}; 

步骤2：明确需要时参考ForumFilter “父” 的方法：

// "child class" implementation 
function ForumFilterTest() {} 
ForumFilterTest.prototype = new ForumFilter(); 
ForumFilterTest.prototype.setRuleFailed = function(ruleName) { 
    // Call parent 
    ForumFilter.prototype.setRuleFailed.call(this, ruleName); 
    // Record that this one has triggered 
    this.triggered.push(ruleName); 
};