Node JS Tryouts | Fetching all search result page result, sorting by ascending and dumping to console. Node JS

fetch.all.pages.of.jsonmock.searchresult.js

/****
 * fetching all pages of search result ...
 * Node JS tryouts.... 
 * https://repl.it/@teswar/fetchallpagesofjsonmocksearchresult
 ************/

const https = require('https');

/*
 * compose url with query params appended...
 */
function composeURL(searchText, pageNumber) {
    return `https://jsonmock.hackerrank.com/api/movies/search/?${[['Title', searchText], ['page', pageNumber]].filter(m => (m[1])).map(m => m.join('=')).join('&')}`;
}

/*
 * returns a promise to resolving json response ...
 */
function fetchJson(url) {
	return new Promise((resolve, reject) => {
		https.get(url, res => {
		  var body = "";
		  res.setEncoding("utf8");
		  res.on("data", (data) => body += data);
		  res.on("end", () => resolve(JSON.parse(body)));
		})
		.on('error', (e) => reject(e))		
	});
}

/*
 * returns a ALWAYS successfully resolving promise.
 * wraps rejected result to resolve null..
 */
function tryFetchJson(url) {
	return fetchJson(url).then((data) => data, (error) => Promise.resolve(null));
}

/*
 * fetches all pages and returns a them as a promise.
 */
async function fetchUntilDead(substr) {
	var metadata = metadata || {
		_isCompleted: function() {
			return !!this.page && this.page >= this.total_pages;
		}
	};

	while(!metadata._isCompleted()) {
		var data = null;
		if(data = await tryFetchJson(composeURL('spider', (metadata.page || 0) + 1))) { 
			data.data = data.data.map(m => m.Title);
			data.page = +(data.page || 0) // parsing to number....

			Array.prototype.push.apply((metadata.data = metadata.data || []), data.data);
			delete data['data'];
			Object.assign(metadata, data);
		}
	}
	return metadata;
}


async function getMovieTitles(substr) {	
	console.log((await fetchUntilDead(substr)).data.sort((a, b) => a.localeCompare(b)));
}

/*
 * invoking.... 
 */
getMovieTitles('spider');

live @ https://repl.it/@teswar/fetchallpagesofjsonmocksearchresult