目录
ES6数组操作：forEach、map、filter、find、every、some、reduce详细用法
1、forEach
2、map
3、filter
4、find
5、every
6、some
7、reduce
8、concat(合并)
ES6数组操作：forEach、map、filter、find、every、some、reduce、concat（合并）详细用法
1、forEach
作用：循环遍历
numbers=[1,2,3,4,5]numbers.forEach(number => {console.log(number) //1 2 3 4 5});
2、map
作用：遍历，类似于forEach
3、filter
作用：过滤筛选数组，返回过滤后的新数组
var products = [{name:"cucumber",type:"vegetable"},{name:"banana",type:"fruit"},{name:"celery",type:"vegetable"},{name:"orange",type:"fruit"}]; var filtered = products.filter((product)=>{return product.type === "vegetable";})console.log(filtered) //[{name:"cucumber",type:"vegetable"},{name:"celery",type:"vegetable"}]
4、find
作用：在数组中找到符合要求的对象 和filter的区别就是找到符合要求的第一个对象就停止寻找了，返回的是一个对象，而filter返回的是所有符合要求的对象组成的新数组
var post = {id:4,title:"Javascript"};var comments = [{postId:4,content:"Angular4"},{postId:2,content:"Vue.js"},{postId:3,content:"Node.js"},{postId:4,content:"React.js"} ];function commentsForPost(post,comments){var v=comments.find(function(comment){return comment.postId === post.id;}) //返回查找到的某一项return v.content; //返回找到的某项的某个值}console.log(commentsForPost(post,comments)); // {postId:4,content:"Angular4"}
5、every
作用：若目标数组中每一个对象都符合设置的条件，则返回true，否则返回false
var users = [{name:"Jill",age:10},{name:"Alex",age:18},{name:"Bill",age:20},{name:"Tony",age:24}];var isAdult_every=users.every(user=>{return user.age>18;})console.log(isAdult_every) //false
6、some
作用：若目标数组中至少有一个符合设置的条件，则返回true，否则返回false
var users = [{name:"Jill",age:10},{name:"Alex",age:18},{name:"Bill",age:20},{name:"Tony",age:24}];var isAdult_some=users.some(user=>{return user.age>18;})console.log(isAdult_some) //true
7、reduce
作用：常用语叠加，可以代替forEach
8、concat(合并)
作用：合并、复制数组；不传参数就是复制，传参数就是合并
var arr1=['a','b','c','d'];var arr2=['d'];var arr3=['e','f'];var cc=arr1.concat(arr2,arr3);console.log(cc);//["a", "b", "c", "d", "d", "e", "f"]
