Node.js（三）Lodash

npm init -y(初始化项目)

npm i --save lodash（引入lodash）

const _=require("lodash");
 
let stus=[
    {id:1,name:"tom",age:40},
    {id:2,name:"xiao",age:28},
    {id:3,name:"gien",age:11},
    {id:4,name:"ovber",age:16},
    {id:5,name:"have",age:26},
];
 
//first输出第一个元素
let f1=_.first([1,2,3]);
console.log(f1);
 
let f2=_.first(stus).age;
console.log(f2);
 
//last输出最后一个元素
let f3=_.last([1,2,3]);
console.log(f3);
 
let f4=_.last(stus).age;
console.log(f4);
 
//findIndex查找元素的索引
let f5=_.findIndex(stus,o=>o.name==="have");
console.log(f5);
 
//find查找元素(只查找第一个)拿到数据
let f6=_.find(stus,o=>o.name.indexOf("o")>0);
console.log(f6);
 
//orderBy排序
let f9=_.orderBy(stus,["age"],["desc"]);
console.log(f9);
 
//sampleSize随机数
let sampleSize=_.sampleSize([1,2,3,4,5,6,7,8,9,10], 3);
console.log(sampleSize);
 
//size返回长度
let size=_.size([1,2,3,4,5,6,7]);
console.log(size);
 
//round四舍五入
let round=_.round(4.06, 2);
console.log(round);
 
//sum计算总和
let sum=_.sum([1,2,3,4,5,6,7,8,9,10]);
console.log(sum);
 
//differenceWith过滤元素
let List=[{'a':1,'b':2,'c':3,'d':'4','e':5},{'a':100,'b':99,'c':520}]
let differenceWith=_.differenceWith(List,[{'a':1,'b':2,'c':3,'d':'4','e':5}], _.isEqual);
console.log(differenceWith);