轻松掌握JavaScript策略模式

 //封装了所有算法的策略对象var strategies = {  'S': function(salary){    return salary*4;  },  'A': function(salary){    return salary*3;  },  'B': function(salary){    return salary*2;  },  'C': function(salary){    return salary*1;  }} //定义自动选择算法的方法var calculateBonus = function(level,salary){  return strategies[level](salary);}//使用calculateBonus('S',9000); //36000calculateBonus('B',5000); //10000 

 //定义验证算法的策略对象var strategies = function(){  isEmpty:function(value,errorMsg){    if(value = ''){      return errorMsg;    }  }  outRangle:function(value,min,max,errorMsg){    if(value.length > max || value.length < min){      return errorMsg;    }  }  isSame:function(oldValue,newValue,errorMsg){    if(newValue !== oldValue){      return errorMsg;    }  }  isMobile:function(value,errorMsg){    if(!/(^1[3|5|8][0-9]{9}$)/.test(value)){      return errorMsg;    }  }  ......} 

 //定义Validatorvar Validator = function(){  this.cache = [];}Validator.prototype.add = function(elem,rules){  var self = this;  for(var i = 0, rule; rule = rules[i++]){    (function(rule){      var strategyAry = rule.strategy.split(':');      var errorMsg = rule.errorMsg;      self.cache.push(function(){        var strategy = strategyAry.shift();        strategyAry.unshift(elem.value);        strategyAry.push(errorMsg);        return strategies[strategy].apply(elem,strategyAry);      })    })(rule)  }}Validator.prototype.start = function(){  for(var i = 0, func; func = this.cache[i++]){    var errorMsg = func();    if(errorMsg){      return errorMsg;    }  }} 

var validator = new Validator();validator.add(elem.userName,[  {strategy:'isEmpty', errorMsg:'用户名不能为空'},  {strategy:'outRangle:6:12', errorMsg:'用户名长度为6-12位'}]);......var errorMsg = validator.start();...... 

 var prop = {  a:55,  b:'ss',  c:function(){...}  d:{x:1,y:2}  ...}foo(prop);