world-grid.js

import * as fs from 'fs';
import { polygon, featureCollection } from '@turf/helpers';
import booleanIntersects from '@turf/boolean-intersects'

const degrees = 6

const featureArray = []

// create a geojson feature collection using TurfJS
var collection = featureCollection(featureArray)

fs.readFile(`./ne_110m_land.geojson`, function (err, data) {
    if (err) {
        console.log(err)
    } else {
        let landFeature = featureCollection(JSON.parse(data))['features']['features']
        
        for (let lat = -90; lat <= 90; lat += degrees) {
            for (let lon = -180; lon <= 180 - degrees; lon += degrees) {
                const latNext = (lat + degrees) <= 90 ? lat + degrees : 90
                const lonNext = (lon + degrees) <= 180 ? lon + degrees : 180

                // create a geojson polygon feature using TurfJS
                const feature = polygon([[[lon, lat], [lonNext, lat], [lonNext, latNext], [lon, latNext], [lon, lat]]])
                var isContains = false
                for (const element of landFeature) {
                    isContains = booleanIntersects(element, feature)
                    if (isContains) {
                        break
                    }
                }
               
                if (isContains) {
                    collection.features.push(feature)
                } 
               
            }
        }
        fs.writeFile(`./${degrees}-world-grid.geojson`, JSON.stringify(collection), function (err) {
            if (err) {
                console.error(err)
            }
        })
    }
})