ds-algo-study/DS-n-Algos/Recursion/recursion_problems-master/problems/05-recursive-flatten.js

Just experimenting with publishing a package

/***********************************************************************
Write a recursive function called `flatten` that takes a single array with
any number of nested arrays and returns and array with all the nested
contents on one level.

Examples:

flatten([]); // => []
flatten([1, 2]); // => [1, 2]
flatten([1, [2, [3]]]); // => [1, 2, 3]
***********************************************************************/
//base case: a flat array
//recursive case: a nested array
//recursive step: push elements that are not arrays and flatten elements of arrays



function flatten(arr) {

    let baseArr = [];
    arr.forEach(function (ele) {
        if (Array.isArray(ele)) {
            baseArr.push(...flatten(ele))
        } else {
            baseArr.push(ele);
        }
    });
    return baseArr;
}

/**************DO NOT MODIFY ANYTHING UNDER THIS LINE*****************/
module.exports = flatten;