js对象数组去重

方法一

采用对象访问属性的方法，判断属性值是否存在，如果不存在就添加。

var arr = [{
     key: '01',
     value: '乐乐'
  }, {
     key: '02',
     value: '博博'
  }, {
     key: '03',
     value: '淘淘'
  },{
     key: '04',
     value: '哈哈'
  },{
     key: '01',
     value: '乐乐'
  }];


  //  方法1：利用对象访问属性的方法，判断对象中是否存在key
  var result = [];
  var obj = {};
  for(var i =0; i</div></div></div><p data-lake-id="0a731ff72781dad753a15553b756fe90" style="font-size: 14px; color: rgb(38, 38, 38); line-height: 1.74; letter-spacing: 0.05em; outline-style: none; overflow-wrap: break-word; margin: 0px;"><br></p>

## 方法二 

<p data-lake-id="904b9ab157fb7c0aed2df6d231b75e2b" style="font-size: 14px; color: rgb(38, 38, 38); line-height: 1.74; letter-spacing: 0.05em; outline-style: none; overflow-wrap: break-word; margin: 0px;"><br></p><p data-lake-id="352aa51791413573fcd127235ba934a8" style="font-size: 14px; color: rgb(38, 38, 38); line-height: 1.74; letter-spacing: 0.05em; outline-style: none; overflow-wrap: break-word; margin: 0px;"><strong>采用数组中的reduce方法，遍历数组，也是通过对象访问属性的方法。</strong></p><p data-lake-id="17e1c1afe6fa5a80fd7f08d437a8374e" style="font-size: 14px; color: rgb(38, 38, 38); line-height: 1.74; letter-spacing: 0.05em; outline-style: none; overflow-wrap: break-word; margin: 0px;"><br></p><div data-card-type="block" data-lake-card="codeblock" id="6b84d9ca" data-language="javascript"><div class="lake-codeblock-content" style="border: 1px solid rgb(232, 232, 232); max-width: 750px; color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: rgb(249, 249, 249);"><div class style="color: rgb(89, 89, 89); margin: 0px; padding: 16px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">

``` undefined 
  //  方法2：利用reduce方法遍历数组,reduce第一个参数是遍历需要执行的函数，第二个参数是item的初始值
     var obj = {};
   arr = arr.reduce(function(item, next) {
     obj[next.key] ? '' : obj[next.key] = true && item.push(next);
     return item;
  }, []);
  console.log(arr); // [{key: "01", value: "乐乐"},{key: "02", value: "博博"},{key: "03", value: "淘淘"},{key: "04", value: "哈哈"}] 

参考链接：

https://www.cnblogs.com/le220/p/9130656.html