我的练习题

数组类

const arr = [[1, 2, 3], [400, 500, 600], '-'];
Array.prototype.pai = function(){
return this.reduce((arr,val)=>{return arr.concat(Array.isArray(val)?val.pai():val);},[]);
}
const x = (array=>{
 let newarr = array.pai()
console.log(newarr)
return newarr[newarr.indexOf(500)]
})(arr);

console.log(x);

var arr = ['小明', '小红', '大军', '阿黄'];
console.log(`欢迎${arr.slice(0,arr.length-1).join(',')}和${arr[arr.length-1]}同学！`);

function string2int(s) {
	if(typeof s != 'string) return;
    //意念判断一下s里面有没有非数字..
    return s.split("").map(v=>v.charCodeAt() - '0'.charCodeAt(0)).reduce((x,y)=>x*10+y)
}