bench_geodata.js

const numFeatures = 100;
const numPolygons = 5;
const numRings = 10;
const numPoints = 10000;

console.time('populate storage');
const features = [];

for (let i = 0; i < numFeatures; i++) {
    const feature = [];
    features.push(feature);

    for (let j = 0; j < numPolygons; j++) {
        const polygon = [];
        feature.push(polygon);

        for (let k = 0; k < numRings; k++) {
            const ring = [];
            polygon.push(ring);

            for (let m = 0; m < numPoints; m++) {
                ring.push(Math.floor(Math.random() * 4096));
                ring.push(Math.floor(Math.random() * 4096));
            }
        }
    }
}
console.timeEnd('populate storage');

function forEachPoint(ring, fn) {
    for (let i = 0; i < ring.length; i += 2) {
        fn(ring[i], ring[i + 1]);
    }
}

console.time('flat bbox');
{
    let minX = Infinity;
    let minY = Infinity;
    let maxX = Infinity;
    let maxY = Infinity;
    for (const feature of features) {
        for (const polygon of feature) {
            for (const ring of polygon) {
                for (let i = 0; i < ring.length; i += 2) {
                    const x = ring[i];
                    const y = ring[i + 1];
                    if (x < minX) minX = x;
                    if (y < minY) minY = y;
                    if (x > maxX) maxX = x;
                    if (y > maxY) maxY = y;
                }
            }
        }
    }
}
console.timeEnd('flat bbox');

console.time('each-based bbox');
{
    let minX = Infinity;
    let minY = Infinity;
    let maxX = Infinity;
    let maxY = Infinity;

    function eachFeature(feature) {
        feature.forEach(eachPolygon);
    }

    function eachPolygon(polygon) {
        polygon.forEach(eachRing);
    }

    function eachRing(ring) {
        forEachPoint(ring, eachPoint);
    }

    function eachPoint(x, y) {
        if (x < minX) minX = x;
        if (y < minY) minY = y;
        if (x > maxX) maxX = x;
        if (y > maxY) maxY = y;
    }

    features.forEach(eachFeature);
}
console.timeEnd('each-based bbox');

result.txt

populate storage: 2703.748ms
flat bbox: 275.649ms
each-based bbox: 258.523ms