Max Points on a Line

Problem statement

Given an array of points where points[i] = [xi, yi] represents a point on the X-Y plane, return the maximum number of points that lie on the same straight line.

Example 1:

Input: points = [[1,1],[2,2],[3,3]]Output: 3

Example 2:

Input: points = [[1,1],[3,2],[5,3],[4,1],[2,3],[1,4]]Output: 4

Constraints:

• 1 <= points.length <= 300
• points[i].length == 2
• -104 <= xi, yi <= 104
• All the points are unique.

My solution

/**
 * @param {number[][]} points
 * @return {number}
 */
var maxPoints = function(points) {
    if (points.length < 3) {
        return points.length;
    }
    
    let maxLine = 0;
    
    for (let i = 0; i < points.length; i++) {
        const slopes = {}
        
        for (let j = i + 1; j < points.length; j++) {
            const currentSlope = slope(points[i], points[j])
            
            slopes[currentSlope] = slopes[currentSlope] + 1 || 2;
            maxLine = Math.max(maxLine, slopes[currentSlope])
        }
    }
    
    return maxLine
};

function gcd(a, b) {
    return b === 0 ? a : gcd(b, a % b);
}

function slope(p1, p2) {
    let xDiff = p1[0] - p2[0];
    let yDiff = p1[1] - p2[1];
    
    if (xDiff === 0) {
        return "vertical"
    }
    
    if (yDiff === 0) {
        return "horizontal"
    }
    
    const div = gcd(xDiff, yDiff);
    
    xDiff /= div;
    yDiff /= div;
    
    return xDiff + "/" + yDiff;
}