数组中对象的属性按照字母排序

var arr = [
    {"symbolone": "rb1905", "symboltwo": "rb1910", "name": "螺纹"}, 
    {"symbolone": "a1905", "symboltwo": "a1909", "name": "黄大豆"},
    {"symbolone": "zn1905", "symboltwo": "zn1908", "name": "锌"}
];
function sortArr(arr, sortStr) {
    var bySort = function() {
        return function(o, p) {
            var a = o[sortStr],
                b = p[sortStr];
            if (isNaN(a)) {
                return a.localeCompare(b);
            } else {
                if (a === b) {
                    return 0;
                } else {
                    return a > b ? 1 : -1;
                }
            }
        }
    };
    for (var i = 0; i < arr.length; i++) {
        arr.sort(bySort(arr[i][sortStr]));
    }
}
 
sortArr(arr, 'symbolone');      // 按 symbolone 排序
//sortArr(arr, 'symboltwo');    // 按 symboltwo 排序
// sortArr(arr, 'name');        // 按 中文名 cnName 排序
console.log(arr);

// 简单写法
var person = [
    {name: 'wangw', age: 24},
    {name: 'guofq', age: 26},
    {name: 'gfq', age: 16},
    {name: 'zhangs', age: 18},
    {name: 'lis', age: 22},
    {name: 'allan', age: 4}
]
person.sort(function(a, b){
    return a.name.localeCompare(b.name);
})
console.log(person);


// 得到前天，今天，后天的日期：eg：今天20190325 ， 那么得到前天 20190323 ， 后天 20190327

function num(s) {
    return s < 10 ? '0' + s : s;
}
function GetDateStr(AddDayCount) { 
    var date = new Date(); 
    date.setDate(date.getDate() + AddDayCount);//获取AddDayCount天后的日期 
    var y = date.getFullYear();
    var m = date.getMonth() + 1;
    var d = date.getDate();
    return y + num(m) + num(d); 
}
console.log("7天前："+GetDateStr(-7));
console.log("前天："+GetDateStr(-2));
console.log("今天："+GetDateStr(0));
console.log("后天："+GetDateStr(+2));