Here's a sample code to fetch the headers. Hope this helps.
const fetch = require("node-fetch");
var myHeaders = new fetch.Headers();
myHeaders.append("Ocp-Apim-Subscription-Key", "ENTER YOUR KEY");
var requestOptions = {
method: 'GET',
headers: myHeaders,
redirect: 'follow'
};
// search results
fetch("https://api.bing.microsoft.com/v7.0/news/search?q=microsoft", requestOptions)
.then(response => response.text())
.then(result => console.log(result))
.catch(error => console.log('error', error));
// response headers
fetch("https://api.bing.microsoft.com/v7.0/news/search?q=microsoft", requestOptions)
.then(response => response.headers)
.then(result => console.log(result))
.catch(error => console.log('error', error));
// BingAPIs-Market
fetch("https://api.bing.microsoft.com/v7.0/news/search?q=microsoft", requestOptions)
.then(response => response.headers.get('bingapis-market'))
.then(result => console.log(result))
.catch(error => console.log('error', error));