first problem description

problems/hello_world/problem.txt

@@ -0,0 +1,73 @@
+In Node.js and browsers there is three ways to do {bold}asynchronous{/bold} JavaScript.
+
+The first way leads to what we call {italic}Callback Hell{/italic}. Callback Hell
+can be minimized by following the tips at http://callbackhell.com.
+
+Another method is to use a Promise package. Using promises will simplify your
+code but it also adds another layer of abstraction.
+
+The last method is by using the async package by Caolan McMahon.  With {italic}async{/italic}
+we are still writing callbacks but without falling into the callback hell or
+adding another layer of abstraction with promises.
+
+More often than not you will need to do multiple asynchronous calls one after
+the other with each call dependant on the result of previous asynchronous call.
+We can do this with the help of async.waterfall.
+
+For example the following code will do a GET request to http://localhost:3131
+in the first waterfall function. The response body is pased as an argument to
+the next waterfall function via the callback. The second function in the waterfall
+accepts the body as a parameter and JSON.parse's it to get to the port
+property then it does another GET request.
+
+    var http = require('http'),
+      , async = require('async');
+
+    async.waterfall([
+      function(cb){
+        var body = '';
+
+        // response is JSON encoded object like the following {port: 3132}
+        http.get("http://localhost:3131", function(res){
+
+          res.on('data', function(chunk){
+            body += chunk.toString();
+          });
+
+          res.on('end', function(){
+            cb(null, body);
+          });
+        }).on('error'), function(e) {
+          cb(err);
+        });
+      },
+
+      function(body, cb){
+        var port = JSON.parse(body).port;
+
+        var body = '';
+
+        http.get("http://localhost:" + port, function(res){
+          res.on('data', function(chunk){
+            body += chunk.toString();
+          });
+
+          res.on('end', function(){
+            cb(null, body);
+          });
+
+        }).on('error'), function(e) {
+            cb(err);
+          });
+      }
+    ], function(err, result){
+      if (err) return console.error(err);
+      console.log(result);
+    });
+
+
+
+In this problem you will need to write a program that first reads the contents of a file.
+The path will be provided as the first command-line argument to your program.
+The file will contain a single URL. Using `http.get` create GET request to to this url and
+console.log the response body.