What to hand in, and how to hand it in

• Make a directory ~fcshome/cs2613/assigments/A3 (i.e. in your git repo for this class). All files related to this assigment should be saved in that directory.
• Make sure you commit and push all your work using coursegit before 5PM on Friday October 20.

Marking

• This assignment will be worth 5% of your final grade.
• You will be marked on the last version pushed to coursegit
• You will be marked on

  coding style

  Follow the Crockford style guide

  correctness and implimentation detail

  You are asked to impliment things in a specific way in Part 1.

  functional javascript

  Part of the point of the assignment is to see that a certain tasks can be accomplished in a very similar way in JavaScript as in Racket. So don't go crazy with mutation.

  test design

  In part 3 you are asked to think about the given suite and improve it. Some questions you might ask

  • How is the coverage?
  • Are the tests robust? Could they fail under certain circumstances not indicating incorrect code?
  • Are the tests easy to understand (particularly if you expand the given set).

Part 1: Flatten

Write a function flatten that produces an array containing all of the elements of all of the nested arrays in an array. For full marks your solution should use recursion. Your function should pass the following jasmine tests

describe("flatten",
     function () {
         it("base case",
        function () {
            expect(ms.flatten([])).toEqual([]);
        });
         it("single element",
        function () {
            expect(ms.flatten([1])).toEqual([1]);
            expect(ms.flatten(["foo"])).toEqual(["foo"]);
            expect(ms.flatten([{foo: 1}])).toEqual([{foo: 1}]);                     
        });
         it("longer list, no mutation",
        function () {
            var data = [[[1],2,[3]],4,[5,6]];
            var orig_data = data;
            expect(ms.flatten(data)).toEqual([1,2,3,4,5,6]);
            expect(data).toEqual(orig_data);
        });
     });

Part 2: Mail Summarize, Again

• For this part use the same 3 sample JSON files as for assignment 2.

  • example1.json
  • example2.json
  • example3.json

• Write a function summarize_mail that reads one of these JSON file and returns a list of objects with with the specified properties. I recommend using the function flatten from Part 1. You will probably also want to borrow the function read json file Your function should pass the following tests.

describe("summarize_mail",
     function() {
         it("no headers",
        function () {
            expect(ms.summarize_mail("example1.json")).toEqual([{}, {}, {}]);
            expect(ms.summarize_mail("example2.json")).toEqual(Array(10).fill({}));
        });
         it("Subject",
        function () {
            expect(ms.summarize_mail("example1.json",'Subject')).toEqual([{Subject: "[notmuch] archive"},
                                          {Subject: "Re: [notmuch] archive"},
                                          {Subject: "Re: [notmuch] archive"}]);
        });
         it("Subject, Date",
        function () {
            expect(ms.summarize_mail("example1.json",'Subject','Date')).toEqual(
            [{Subject: "[notmuch] archive", Date: 'Tue, 17 Nov 2009 18:21:38 -0500'},
             {Subject: "Re: [notmuch] archive", Date: 'Tue, 17 Nov 2009 18:04:31 -0800'},
             {Subject: "Re: [notmuch] archive", Date: 'Wed, 18 Nov 2009 02:22:12 -0800'}]);
        });
     });

Part 3: Testing

Impliment (and explain in your commit message) two improvements to the test suite for summarize_email.