Merge and sort arrays

const array = [[3,2,1], [6,5,4]];

let mergedArrays = [];

for(let i = 0; i < array.length; i++) {
    for(let j = 0; j < array[i].length; j++) {
        mergedArrays.push(array[i][j]); 
    }
}

for(let i = 0; i < mergedArrays.length; i++) {
    for(let j = 0; j < mergedArrays.length; j++) {
        let tempNum = null;
        
        if(mergedArrays[j] > mergedArrays[j + 1]) {
            tempNum = mergedArrays[j];
            mergedArrays[j] = mergedArrays[j + 1];
            mergedArrays[j + 1] = tempNum;
        }
    }
}

console.log(mergedArrays);