cjavdev's solution to Gigasecond on the JavaScript track

Instructions

Test suite

Solution

Note:

This solution was written on an old version of Exercism. The tests below might not correspond to the solution code, and the exercise may have changed since this code was written.

Calculate the moment when someone has lived for 10^9 seconds.

A gigasecond is 10^9 (1,000,000,000) seconds.

Setup

Go through the setup instructions for JavaScript to install the necessary dependencies:

http://exercism.io/languages/javascript/installation

Running the test suite

The provided test suite uses Jasmine. You can install it by opening a terminal window and running the following command:

npm install -g jasmine

Run the test suite from the exercise directory with:

jasmine gigasecond.spec.js

In many test suites all but the first test have been marked "pending". Once you get a test passing, activate the next one by changing xit to it.

Source

Chapter 9 in Chris Pine's online Learn to Program tutorial. http://pine.fm/LearnToProgram/?Chapter=09

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

gigasecond.spec.js

var Gigasecond = require('./gigasecond');

describe('Gigasecond', function () {
  it('tells a gigasecond anniversary since midnight', function () {
    var gs = new Gigasecond(new Date(Date.UTC(2015, 8, 14)));
    var expectedDate = new Date(Date.UTC(2047, 4, 23, 1, 46, 40));
    expect(gs.date()).toEqual(expectedDate);
  });

  xit('tells the anniversary is next day when you are born at night', function () {
    var gs = new Gigasecond(new Date(Date.UTC(2015, 8, 14, 23, 59, 59)));
    var expectedDate = new Date(Date.UTC(2047, 4, 24, 1, 46, 39));
    expect(gs.date()).toEqual(expectedDate);
  });

  xit('even works before 1970 (beginning of Unix epoch)', function () {
    var gs = new Gigasecond(new Date(Date.UTC(1959, 6, 19, 5, 13, 45)));
    var expectedDate = new Date(Date.UTC(1991, 2, 27, 7, 0, 25));
    expect(gs.date()).toEqual(expectedDate);
  });

  xit('make sure calling "date" doesn\'t mutate value', function () {
    var gs = new Gigasecond(new Date(Date.UTC(1959, 6, 19, 5, 13, 45)));
    var expectedDate = new Date(Date.UTC(1991, 2, 27, 7, 0, 25));
    gs.date();
    expect(gs.date()).toEqual(expectedDate);
  });
});

function Gigasecond(birthDay) {
    this.birthDay = birthDay;
}

Gigasecond.prototype.date = function() {
    var birthDaySeconds = this.birthDay.getTime() / 1000,
        gigaDaySeconds = birthDaySeconds + Math.pow(10, 9);
    return new Date(gigaDaySeconds * 1000);
};

module.exports = Gigasecond;

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to Gigasecond in the JavaScript Track