Flatten Array

flatten.js

/**
 * Recursive function to flatten the current array level
 * @param {Array<any>} arr - The array to flatten
 * @returns {Array<any>} New flattened array
 */
const flatten = (arr) => {
  const newArray = [];
  arr.forEach((item) => {
    if (Array.isArray(item)) {
      newArray.push(...flatten(item));
    } else {
      newArray.push(item);
    }
  });
  
  return newArray;
};


module.exports = {
  flatten: flatten
};

run.js

const { flatten } = require('./flatten');

const arr = [[1,2,[3]],4];
const flattedArray = flatten(arr);