...可以将类数组对象迅速转换成数组
window.onload=function(){
let aLi = document.querySelectorAll('ul li');
let arrLi = [...aLi];
arrLi.pop();//删除一项
arrLi.push('aasdf');//末尾增加一项
console.log(arrLi);//[li,li,li,aasdf]
}
复制代码Array.from()可以将类数组对象迅速转换成数组
类数组：通常具有length
let arr=[1,2,3];
let arr2=[...arr];
let arr3 = Array.from(arr);//[1,2,3]
复制代码 window.onload=function(){
let aLi = document.querySelectorAll('ul li');
let arrLi = Array.from(aLi);//ES6
let arrLi = [].slice.call(aLi);//ES5
arrLi.pop();
arrLi.push('aasdf');
console.log(arrLi);
}
复制代码 function show(){
let args=Array.from(arguments);
console.log(args);
};
show(1,2,3,4,5);
复制代码 let str= 'strive';
// let arr=str.split('');
let arr = Array.from(str);//把类数组变成数组
console.log(arr);
复制代码Array.of可以将一组值转换成数组
let arr=Array.of('apple','banana','orange');//把一组值转化成数组
console.log(arr);
复制代码arr.find查找第一个符合条件的值，如果没有找到，返回undefined
let arr1=[2,4,7,1,6];
let res=arr1.find((val,index,arr)=>{
return val>5;
});
console.log(res);//7
复制代码arr.findIndex查找第一个符合条件的选项，返回索引值,没找到返回-1
let arr2=[2,4,7,1,6];
let ress=arr2.findIndex((val,index,arr)=>{
return val>5;
});
console.log(ress);//2
复制代码arr,fill(填充的东西，开始位置，结束位置)
let arr3 = new Array(10);
arr3.fill('默认值');
console.log(arr3);//(10) ["默认值", "默认值", "默认值", "默认值", "默认值", "默认值", "默认值", "默认值", "默认值", "默认值"]
let arr4=arr3.fill('haha',1,4);
console.log(arr4);//(10) ["默认值", "haha", "haha", "haha", "默认值", "默认值", "默认值", "默认值", "默认值", "默认值"]
复制代码ES2016里新增arr.includes
let arr5 = ['apple','banana','orange','strawberry'];
let b=arr5.includes('orange222');
console.log(b);//false
复制代码