我的作业6

1、

var a=1, b=[2,3], c=[4,5], d=6; 写入一个函数，将abcd以实参传入返回[1,2,3,4,5,6]

function f1(){
	var arr= [];
	for(var i=0; i<arguments.length; i++){
		arr = [...arr.concat( arguments[i])]
	}			  
	return arr;
}f1(a,b,c,d)

2、

求obj对象中id与arr的和

        var obj = {
          id:5,
          name:'abc',
          sex:'男',
          arr:[1,2,3,4]
        };
        var obj = {
          id:5,
          name:'abc',
          sex:'男',
          arr:[1,2,3,4],
		  getId:function(){
			return this.id	
		},
		   getArr:function(){
			  return this.arr.reduce((prev, curr)=>{return prev+curr;})
        }
		}
		console.log(obj.getId()+obj.getArr())

3、

取二组数据的并集，交集，差集并去重

   var a1 = [1,2,3,4,5,6,4,5,6];
   var a2 = [4,5,6,7,8,9,7,8,9];
   var a3 = Array.from(new Set([...a1, ...a2])) //并集
   var a4 = a2.filter(item => new Set(a1).has(item))//交集
   var a5 = a3.filter(item => !a4.includes(item))//差集去重

4、

各结构的转换

const m1 = new Map([['a',1],['b',2],['c',3]]);

1. map类型转为数组

var arr = […m1]//map转数组

2. map类型转为object

var obj ={}
   for(let (k,v) of m1){
	obj[k]=v;
	}//map转对象

3. object转为map

let obj = {"name":"jindu", "qq":"2429462491"};
var map1 = new Map();
for(let k in map1){
	map1.set(k,obj[k]);// obj 转map
}

4. set类型转为数组

const set = new Set([1, 2, 3, 4, 5]);
  var arr = Array.from([…set])

5、

var id = Symbol('jindu');
var o = {
    [id] :'hello world',
    id:'abc'
}

请求出结果：

1)  o.id      
// ‘abc’
2)  o['id']     
// “hello world”
3)  o[id]     
//’abc’

6、

promise解决回调陷阱的链式写法：

    var p = new Promise(function(resolve,reject){
        if(true){  //
            resolve("OK")
        }else {
            reject("error")
        }
    });
    p.then(function(data){  
        console.log(data)   //
        return new Promise(function(resolve,reject){
            if(true){  //
                resolve(1)
            }else {
                reject(2)
            }
        });
    })

7、

Promise对象实现Ajax封装

const f1 = function(url, type, data){
	const promise = new Promise(function(resolve, reject){
	xmlHttp.open(type, url){
		if(type =='get'){.     //type get
            xmlHttp.send();  //get模式带param参数
        }else {            //type post
            xmlHttp.setRequestHeader("Content-Type", "application/json");//如post参数还有multipart/form-data其使用body调用
            xmlHttp.send(JSON.stringify(data));// 
        };
        xmlHttp.responseType = "json";
        xmlHttp.onreadystatechange =function(){ //ajax请求
          if (xmlHttp.readyState == 4){
          	if (xmlHttp.status === 200) {
            	resolve(xmlHttp.response);
          	} else {
            	reject(new Error(xmlHttp.statusText));
          	}
		}
        };
		}
	}return promise;
}