The result is ReferenceError  because JS has asked SCOPE by LOOKING-UP and
traversing from the current scope to the global scope and has not found any declaration for variable 'b'.

However, for 'c' there is an assigned value and JS has looked-up to scope upto the global level and in
non-strict mode of JS, the compiler has created a variable declaration for 'c' and has given it to foo.

This week there is only one entry from us. This is a super 4 hrs video from Microsoft on Building Angular2 apps using TypeScript. If you are someone who hasn't written any piece of code in Angular 1x or who missed it can pick it up clearly from here..

Writing code is an exciting. It is even more exciting when everything is going well from dev to production.

However, all of us have to agree that at one or the other stage when a defect pop's up,  we all have one statement as our defence - "It works well on my machine". However, we forget one tiny but important aspect of development - writing unit test cases for our code.

Many out there believe that unit testing is time consuming and hilariously funny to talk about. When I started out my career as a software Engineer/ Systems Engineer, I disliked my manager when he asked me about the status of my unit test cases. I clearly had a disliking for that. However, 8 years into developing products for large clients ranging from Banking to automotive, I strongly believe that a developer's good healthy sleep lays in good and healthy unit test cases.


So over the coming days, I am making screencasts on writing unit test cases in Node.js using Mocha and Chai. Mocha and Chai are 2 wonderful unit test frameworks for Node.js. Mocha is a JavaScript library for organising our code for both serverside as well as client side JavaScript code. Chai.js is a rich with many assertions for validating our code. Both Mocha and Chai support TDD and BDD style of unit testing.

Here is the Part 3 of the our unit testing nodejs with Mocha and Chai