打平多维数组的常用方式

reduce 方式

const arr = [1,2,[3,4,5,[6,7,[8]]]];
function fn(arr){
    return arr.reduce((prev,cur)=>{
        return prev.concat(Array.isArray(cur) ? fn(cur) : cur)
    },[])
}
fn(arr);
// [1, 2, 3, 4, 5, 6, 7, 8]

循环方式

const arr = [1,2,[3,4,5,[6,7,[8]]]];
function fn(arr){
    const temp = [...arr];
    let resAry = [];
    for(let i=0;i<temp.length;i++){
        const cur = temp[i];
        if(Array.isArray(cur)){
            temp.push(...cur)
        }else{
            resAry.push(cur)
        }
    }
    return resAry;
}
fn(arr);
// [1, 2, 3, 4, 5, 6, 7, 8]

function fn1(ary) {
    var arr = [];
    const each = (data) => {
        if (!Array.isArray(data)) {
            arr.push(data);
            return
        };
        data.forEach(item => {
            each(item);
        })
    }
    each(ary)
    return arr;
}
fn1(arr);
// [1, 2, 3, 4, 5, 6, 7, 8]

toString 方式

const arr = [1,2,[3,4,5,[6,7,[8]]]];
arr.toString();
// '1,2,3,4,5,6,7,8'

join 方式

const arr = [1,2,[3,4,5,[6,7,[8]]]];
arr.join(',');
// '1,2,3,4,5,6,7,8'