N维数组扁平化

ES6方法flat()

let arr = let arr = [1,2,['a','b',['c','d',[2,[2,3,4]]]]];
arr.flat(Infinity);//[1, 2, "a", "b", "c", "d", 2, 2, 3, 4]

遍历

            let arr = [1,2,['a','b',['c','d',[2,[2,3,4]]]]];
            let newArr = [];
            function flatten(arr){
                arr.forEach(val=>{
                    if(Array.isArray(val)){
                        flatten(val);
                    }else{
                        newArr.push(val);
                    }
                })
                return newArr
            }