WebSocket Day04 : 消息推送

1.数字数组去重 

var arr = [11,11,22,33]
function unique(arr) {
    return arr.filter(function (ele, index, array) {
        return array.indexOf(ele) === index
    })
}
unique(arr);

2.对象数组去重 

var objArr = [{name:1,num:1},{name:1,num:1},{name:2,num:2}];
const removeDuplicateObj = (arr) => {
  let obj = {};
  arr = arr.reduce((newArr, next) => {
    obj[next.id] ? "" : (obj[next.id] = true && newArr.push(next));
    return newArr;
  }, []);
  return arr;
};
removeDuplicateObj(objArr);

3. 将字符串转成数组 

Array.from("将字符串转成数组");//["将", "字", "符", "串", "转", "成", "数", "组"]

4.找到数组的最大和最小值，仅适用于单数字数组 

let min = arr.sort((a, b) => a - b)[0];
let max = arr.sort((a, b) => b - a)[0];

5.将一个数组中的每个undefined,‘’,0,false,null的元素过滤掉 

let list = [1, "", undefined, 11341];
arr.filter(Boolean); //[1,11341]