比较直观的解法

var sortedSquares = function(A) {
   return A.sort((a, b)=>{
        return Math.abs(a) -Math.abs(b)
    }).map(function(el){
       return el * el
   })
};

另一个，从左右两端开始比较，可能是-123与124比较，然后是-123与122

var sortedSquares = function(A) {
    let left = 0;
    let right = A.length - 1;
    const result = new Array(A.length);
    let index = A.length - 1;
    while (left <= right) {
        const leftSquare = A[left] * A[left];
        const rightSquare = A[right] * A[right];
        if (leftSquare > rightSquare) {
            result[index] = leftSquare;
            left++;
        } else {
            result[index] = rightSquare;
            right--;
        }
        index--;
    }
    return result;
};