【Javascript】覚書

車輪置き場

配列をまわして順番に値を取り出す

Rotate.js

/**
 * 配列を回して順番に値を取り出す
 */
Rotate = function(arr){
    if(!(this instanceof Rotate)) {
        return new Rotate();
    }

    // private
    var _rotator = 0;
    var _arr = arr || [undefined];
    var _rotatormax = _arr.length;

    //public
    this.length = _arr.length;

    //public
    this.get = function(reload){
        var c = _arr[_rotator];
        if (true===reload) this.next();
        else if (false===reload) this.prev();
        return c;
    };
    this.next = function(i){
        if (i===undefined) i=1;
        _rotator = (_rotator+i)%_rotatormax;
        return this;
    };
    this.prev = function(i){
        if (i===undefined) i=1;
        _rotator = (_rotator+_rotatormax-i)%_rotatormax;
        return this;
    };
    this.getRotator = function(){
        return _rotator;
    };
};

使用例

var x = new Rotate(["sora","A","ankimo"]);

console.log(x.get(true))
console.log(x.get())
console.log(x.get(true))
console.log(x.get(false))
console.log(x.get(false))
console.log(x.get(false))

jQueryで条件分岐を実現する

jquery.if.js

;(function($){
$.fn.extend({
  if:function(b, f1, f2){
    if(b){
      f1.call(this);
    }else{
      f2.call(this);
    }
    return this;
  },
  switch:function(c, opt){
    def = {default:function(){}};
    opt = $.extend(def,opt);
    
    if (c in opt){
      opt[c].call(this);
    } else {
      opt['default'].call(this);
    }
    return this;
  }
});
})(jQuery);

使用例

$("a").if(true, 
  function(){console.log(this)},
  function(){alert("false")}
)
.switch("case1",{
  case1:function(){alert('case1')},
  default:function(){alert('default')}
});