var foo = [1,[2,3],['4',5,['6',7,[8]]],[9],10];
//方法1
//限制：数组项不能出现','，同时数组项全部变成了字符数字
foo.toString().split(',');//["1","2","3","4","5","6","7","8","9","10"]
//方法2
//转换后数组项全部变成数字了
eval('[' + foo + ']');//[1,2,3,4,5,6,7,8,9,10]
//方法3，使用ES6展开操作符
//写法太过麻烦，太过死板
[1, ...[2, 3], ...['4', 5, ...['6',7,...[8]]], ...[9], 10]; // [1, 2, 3, "4", 5, "6", 7, 8, 9, 10]
//方法4
JSON.parse(`[${JSON.stringify(foo).replace(/\[|]/g, '')}]`);//[1,2,3,"4",5,"6",7,8,9,10]
//方法5
const flatten = (ary) =>ary.reduce((a,b)=>a.concat(Array.isArray(b) ? flatten(b) : b), []);
flatten(foo);//[1,2,3,"4",5,"6",7,8,9,10]
//方法6
function flatten(a){
return Array.isArray(a) ? [].concat(...a.map(flatten)) : a;
}
flatten(foo);//[1,2,3,"4",5,"6",7,8,9,10]
