array_dups_sort created by ValentynaGorbachenko - https://repl.it/DoVE/1

array_dups_sort.js

/**
* Implement function with 1 argument typeof <Array> 
* 1. function should delete all duplicating elements 
* 2. function should remove all not Number values
* 3. function should sort array from the largest to the smallest number.
* For example: given array [1, 1, 3, 2, 'qwe', 6, true, 4, 2], result function should return [6, 4, 3, 2, 1]
*/

var arrayNotSorted = ['ggg', 'rtty', 1, 1, 1, 3, 2, 6, true, 4, 2];//I added few elements
var arraySorted; // If we like to save the incoming data

function myFuncSort(myArray) {
	if (myArray instanceof Array){ // (Array.isArray(myArray)) another condition
		var myArrayTemp = myArray.slice(); // coping the incoming array
		// #2 version uses undefined
		// Number check #2
		for(let i=0; i<myArrayTemp.length; i++){
			if (typeof myArrayTemp[i] !== 'number') { // checking if array element is not a number
					myArrayTemp[i] = undefined; // if(typeof myArrayTemp[i] !=== 'number' || isNaN(myArrayTemp[i]))
			}
		}
		
		// Duplicates check #2
		for(let i=0; i<myArrayTemp.length; i++){
			if (myArrayTemp[i] != undefined){
				for(let j=i+1; j<myArrayTemp.length; j++){
					if (myArrayTemp[i] == myArrayTemp[j] && myArrayTemp[j] != undefined){	// deleting all duplicated elements
						myArrayTemp[j] = undefined;
					}
				}
			}
		}
		
		// Deleting undefined #2
		myArrayTemp = myArrayTemp.filter(function(elem){
			if (elem != undefined){
				return elem;
			}
		});
		
		// #1 version uses method splice, which might be a bit heavy if array has a big number of elements
		/*
		// Number check #1
		for(var i=0; i<myArrayTemp.length; i++){
			if (typeof myArrayTemp[i] !== 'number') { // checking if array element is not a number
					myArrayTemp.splice(i--,1);
			}
		}
		
		// Duplicates check #1
		for(var i=0; i<myArrayTemp.length; i++){
			for(var j=i+1; j<myArrayTemp.length; j++){
				if (myArrayTemp[i] == myArrayTemp[j]){	// deleting all duplicated elements
					myArrayTemp.splice(j--,1);
				}
			}
		}
		*/
		
		// Sort in the reverse order #1 and #2
		myArrayTemp.sort(function(a, b){return b-a}); // reversing the array elements
		
		return myArrayTemp;
		
	} else {
		// Error message
		console.log("Error - incoming data is not an array!");
	}
}
console.log(arrayNotSorted);
arraySorted = myFuncSort(arrayNotSorted);
console.log(arrayNotSorted);
console.log(arraySorted);