JS实现JSON数组合并和去重

var a=[{"id":"1001","name":"张三","age":"18","address":"北京市朝阳区","school":"朝阳区第二中学"},{"id":"1002","name":"李四","age":"15","address":"北京市海淀区","school":"海淀区第二中学"},{"id":"1003","name":"王五","age":"16","address":"北京市石景山区","school":"石景山区第二中学"}];
            var b=[{"id":"1004","name":"小毛","age":"18","address":"北京市朝阳区","school":"朝阳区第二中学"},{"id":"1003","name":"王五","age":"16","address":"北京市石景山区","school":"石景山区第二中学"}]
            var c = a.concat(b); //合并数组
            var temp = {}; //存放id
            var result = []; //新数组
            c.map((item,index) => {
                if(!temp[item.id]){
                    result.push(item);
                    temp[item.id] = true;
                }
            })
            document.getElementById('txt').innerHTML = JSON.stringify(result)

有两个json数组demo1和demo2

var demo1 = [{"id": 0, "name": "牛肉"},{"id": 1,"name": "羊肉"}];

var demo2 = [{"id": 2, "name": "牛肉"},{"id": 3,"name": "鱼肉"},{ "id": 4,"name":"鸡肉"}];
数组合并
var totalDemo = demo1.concat(demo2);
console.log(totalDemo); //[{"id": 0, "name": "牛肉"},{"id": 1,"name": "羊肉"},{"id": 2, "name": "牛肉"},{"id": 3,"name": "鱼肉"},{ "id": 4,"name":"鸡肉"}]
数组合并用的是concat方法，它可以用于字符串之间的连接和数组之间的连接。

数组去重
上面已经得到合并的数组 totalDemo ，去掉name属性是一样的json对象

var temp = {};   //用于name判断重复
var result = [];  //最后的新数组

totalDemo.map(function (item, index) {
    if(!temp[item.name]){
        result.push(item);
        temp[item.name] = true;
    }
});

console.log(result);//[{"id": 0, "name": "牛肉"},{"id": 1,"name": "羊肉"},{"id": 3,"name": "鱼肉"},{ "id": 4,"name":"鸡肉"}];
map方法：按照原始数组元素顺序依次处理元素。可以在map方法里面输入console.log(item)打印看下，它会把数组中的对象依次打印出来。