Given a n x m binary matrix filled with 0s and 1s, find the largest rectangle containing only 1s and return its area.

largest-rect.js

function largestRect(matrix, match = "1") {
    let maxArea = 0
    for (let y1 of matrix.keys()) {
        for (let x1 of matrix[y1].keys()) {
            if (matrix[y1][x1] !== match) continue
            for (var x2 = x1; matrix[y1][x2 + 1] === match; x2++) continue
            for (var y2 = y1; matrix[y2 + 1]?.slice(x1, x2 + 1).every(a => a === match); y2++) continue
            maxArea = Math.max(maxArea, (x2 - x1 + 1) * (y2 - y1 + 1))
        }
    }
    return maxArea
}