web/public/gis/static/threeMap/merge.js

import TL from './TL_BOUND.json' assert {type: 'json'};
import JL from './JL_BOUND.json' assert {type: 'json'};
import fs from 'fs'
import * as geojsonMerge from '@mapbox/geojson-merge'

var mergedGeoJSON = geojsonMerge.merge([
    TL,
    JL
]);

console.log(JSON.stringify(mergedGeoJSON));

fs.writeFile( 'merge.json', JSON.stringify(mergedGeoJSON), function (err) {
    if (err) {
        console.log('文件写入失败：' + err.message);
    }

    console.log('文件写入成功！')
})