Clearing A Array And Reduce Array Elements, Flatten The Nested Array

Various functions that can be used to reduce an array and clearing junk values in Array. Also describes flatten multiple nested array.

Many times while developing, we face issue in clearning the return objects or Array, This ariticles deals with clearing junk values,removing null,undefined or creating a custom "Array" function to do all.

 

Best way to get any filter values from Array of any particular data type is to use filter method [especially Number and truthy/falsely value] 

var t = [1,2.3,5,null,"",undefined,"hello","v","C#"]
t.filter(Boolean) // Output will be [1, 2.3, 5, "hello", "v", "C#"]

t.filter(Number)
[1, 2.3, 5] //Output with just Number datatype

Working with Nested Arrays, it is always easy to working in numbers rather than string type.One of fastest way to reduce nested array is to convert to string value and use split operator. 

[[[0], [1]], [[2], [3]], [[4], [5]]].toString().split(",").map(Number)
// Output will be [1, 2, 3, 4, 5]  it will be typeof Number

//When output is needed to be in String the split operation itself suffice

[[[0], [1]], [[2], [3]], [[4], [5]]].toString().split(",")
["0", "1", "2", "3", "4", "5"] // Output in string format

[[[["asfdsadf"]]],["test"]].toString().split(",")
["asfdsadf", "test"] // Result

[].concat.apply([], [3,4,4,[4],[5],[7]);
//[3,4,4,4,5,7] Output it works well for single nested array

var testSingleNestedArr = [["d"],[4],["Hello"]]
[].concat.apply([],testSingleNestedArr)
["d", 4, "Hello"] // Without changing the datatype

the chanllege comes only if the nested array is more nested

function faltTheArr(arr) {
    return arr.reduce(function (acc, cur) {
        return acc.concat(Array.isArray(cur) ? faltTheArr(cur) : cur);
    }, []);
}

faltTheArr([[[1,[2.2]],3,4,5], [6,4,5]]); // [1, 2.2, 3, 4, 5, 6, 4, 5]

Creating custom Array function clear() 

Array.prototype.clear = function() {
    var i;
    var clearedAr = [];
    for (i = 0; i < this.length; i++) {
    if(this[i]){
        clearedAr.push(this[i]);
        }

    }
   console.log(clearedAr.filter(Boolean).length); // output 4
    return clearedAr.filter(Boolean);
};

var Arr= ["Banana", "Orange", "Apple", "Mango",null,undefined,""];
 Arr =  Arr.clear();
// Value of Arr  ["Banana", "Orange", "Apple", "Mango"]