品一品编程 --- 3

问题描述：

实现链式调用

var origin = [
    {id:1,title:'title1',name:'tom'},
    {id:2,title:'abcd2',name:'d1'},
    {id:3,title:'title2',name:'d34'},
    {id:4,title:'efg',name:'df4'}
];
  
var find = function(data){  
    // your code here  
}  
  
var result = find(origin).where({'title':/\d$/}).order('id','desc'); //desc 非递增  
console.log(result);  //  [{id:3,title:'title2'},{id:1,title:'title1'}]  

程序如下：

var find = function(data){
   var _this = this //减少对全局变量的访问
    _this.data = data
    _this.where = function(obj) {
        var keys = Object.keys(obj) 
        for(var key in keys) { //实现多条件下筛选
            var reg = obj[key]
            _this.data = _this.data.filter(function(x){
                return reg.test(x[key])
            })
        }
        return _this
    }
    _this.order = function(key,type) {
        if(type === 'desc') {
            return _this.data.sort(function(s1,s2) { //降序
                return s2[key] - s1[key]
            })
        }
        else {
            return _this.data
        }
    }
    return {
        data: this.data,
        where: this.where,
        order: this.order
    }
}