欢迎光临散文网 会员登陆 & 注册

【前端面试】当被面试官问到 “数组的 reduce 方法”

2023-06-14 14:38 作者:叶淋2544  | 我要投稿

累加

[1,2,3].reduce((pre,cur) =>{

return pre+cur

},0)


const result = [1,2,3].reduce((pre,cur) => pre+cur);


找最大值

const result = [1,2,3,2,1].reduce((pre,cur) => Math.max(pre,cur) )


数组去重

const resultList = [1,2,3,2,1].reduce((preList,cur) => {

if(preList.indexOf(cur) === -1){

preList.push(cur)

}

return preList

},[])


归类

const dataList = [

{

name:"aa",

country:"China"

},

{

name:"bb",

country:"China"

},

{

name:"cc",

country:"USA"

},

{

name:"dd",

country:"En"

}

]

const reslutObj = dataList.reduce((pre,cur) => {

const {country} = cur;

if(!preObj[country]){

preObj[country] = [];

}

preObj[country].push(cur);

return preObj;

},{});


字符串的反转

const str = "hello world";

const reslutStr = Array.from(str).reduce((pre,cur)=>{

return `${cur}${pre}`;

},'');



【前端面试】当被面试官问到 “数组的 reduce 方法”的评论 (共 条)

分享到微博请遵守国家法律