What is the most efficient way to move the elements within the nested portion of the inner array out into the main array?
Example: [1,[2,3],4] -> [1,2,3,4]
my attempt
var old_arr = ["one", ["two", "three"], "four"];
var new_arr = [];
function arrayfix(arr) {
for (var i = 0; i < arr.length; i++) {
if (typeof arr[i] == typeof {}) { //checks to see if it's an object
for (var j = 0; j < Object.keys(arr[i]).length; j++) {
new_arr.push(arr[i][j]);
}
}
new_arr.push(arr[i]);
}
return new_arr;
}
console.log(arrayfix(old_arr));
actual outcome
[ 'one', 'two', 'three', [ 'two', 'three' ], 'four' ]
desired outcome
[ 'one', 'two', 'three', 'four' ]
There is a built-in prototype function in Array called flat for that purpose.
One parameter: The depth level specifying how deep a nested array structure should be flattened. Defaults to 1.
flat() will flat a 2D to 1D flat(2) will flat out a 3D to 1D.
var old_arr= ["one",["two","three"],"four"];
console.log(old_arr.flat());flat function is what you are looking for.
var old_arr= ["one",["two","three"],"four"];
var new_arr = old_arr.flat();
console.log(new_arr);Either use the Array#flat() method, like Amila Senadheera suggested, or change your function to not always add the element to the new array, like so:
var old_arr= ["one",["two","three"],"four"];
function arrayfix(arr){
let new_arr = [];
for(let i =0; i < arr.length; i++) {
if(typeof arr[i] == typeof {}) { //checks to see if it's an object
for(let j =0; j < Object.keys(arr[i]).length; j++) {
new_arr.push(arr[i][j]);
}
} else { // if it's an array, don't add it back to the new array
new_arr.push(arr[i]);
}
}
return new_arr;
}
console.log(arrayfix(old_arr));