JSFiddle - React, Tailwind, and code Playground
by fxi
HTML
<p id="test">
</p>JavaScript
const elResult = document.getElementById('test');
const urlData = 'https://geoportal.bafg.de/arcgis3/services/GEMSTAT/GEMS_Mean_Annual_Aggregated_Data/MapServer/WFSServer?SERVICE=WFS&VERSION=2.0.0&request=getfeature&typeNames=GEMSPROD.STATION_AGGREGATED_DATA_TABLE&outputFormat=geojson&Filter=%3Cogc:Filter%3E%3Cogc:PropertyIsEqualTo%3E%3Cogc:PropertyName%3EGEMS_STATION_NUMBER%3C/ogc:PropertyName%3E%3Cogc:Literal%3EAFG00001%3C/ogc:Literal%3E%3C/ogc:PropertyIsEqualTo%3E%3C/ogc:Filter%3E'
fetch(urlData)
.then(r=>r.text())
// regex magic
.then(str => str.replace(/,(?=[0-9])/g,'.'))
// parse to object
.then(str => JSON.parse(str))
// convert back to str for display
.then(json => {elResult.innerText = JSON.stringify(json,0,2) })