You can use this to get the Soundcloud permalink from a track ID.

getSoundcloudLink.js

var client_id = ''; // Insert client ID
var track_id = ''; // Insert track ID

var url = 'https://api.soundcloud.com/tracks/' + track_id + '?client_id=' + client_id;
var https = require('https');

https.get(url, function(res) {
	var json = '';

	res.on('data', function(data) {
		json += data;
	});

	res.on('end', function() {
		json = JSON.parse(json);
		console.log(json.permalink_url);
	});
	
}).on('error', function(e) {
	console.log('Error: ', e);
});