An alternative to .push()

preset_array.js

function solution(A) {
    var n = A.length - 1,
        lSum = 0, 
        rSum = 0,
        diffs = new Array(n),
        diff,
        min = Infinity;
    for (var p = 0; p < n; p++) {
        lSum += A[p];
        rSum += A[n - p];
        diffs[p] = diffs[p] || 0;
        diffs[n - p - 1] = diffs[n - p - 1] || 0; 
        diffs[p] += lSum;
        diffs[n - p - 1] -= rSum;
    }
    for (var i = 0; i < diffs.length; i++) {
        diff = Math.abs(diffs[i]);
        min = diff < min ? diff : min;
    }
    return min;
}