Exercise Solutions: TypeScript¶

Part 1 - Declare Variables With Type¶

1. Declare the variables with type based on the information given in the table.

   1let spacecraftName: string = 'Determination';
   2let speedMph: number = 17500;
   3let kilomitersToMars: number = 225000000;
   4let kilometersToTheMoon: number = 384400;
   5let milesPerKilometer: number = 0.621;
   

Part 2 - Print Days to Mars¶

2. Use a template literal to print variables.

   console.log(`${spacecraftName} would take ${daysToMars} days to get to Mars.`);
   

Part 3 - Create a Function¶

1. In the space indicated, define a function that calculates the days it would take to travel to a location.

   1function getDaysToLocation(kilometersAway: number): number {
   2   let milesAway: number = kilometersAway * milesPerKilometer;
   3   let hours: number = milesAway / speedMph;
   4   return hours / 24;
   5}
   

Part 4 - Create a Spacecraft Class¶

Create a Spacecraft class.

 1class Spacecraft {
 2   milesPerKilometer: number = 0.621;
 3   name: string;
 4   speedMph: number;
 5
 6   constructor(name: string, speedMph: number) {
 7      this.name = name;
 8      this.speedMph = speedMph;
 9   }
10
11   getDaysToLocation(kilometersAway: number): number {
12      let milesAway: number = kilometersAway * this.milesPerKilometer;
13      let hoursToMars: number = milesAway / this.speedMph;
14      return hoursToMars / 24;
15   }
16}

Part 5 - Export and Import the SpaceLocation Class¶

After following the steps in Part 5, your Spacecraft class should look slightly different:

 1class Spacecraft {
 2   milesPerKilometer: number = 0.621;
 3   name: string;
 4   speedMph: number;
 5
 6   constructor(name: string, speedMph: number) {
 7      this.name = name;
 8      this.speedMph = speedMph;
 9   }
10
11   getDaysToLocation(kilometersAway: number): number {
12      let milesAway: number = kilometersAway * this.milesPerKilometer;
13      let hours: number = milesAway / this.speedMph;
14      return hours / 24;
15   }
16
17   printDaysToLocation(location: SpaceLocation) {
18      console.log(`${this.name} would take ${this.getDaysToLocation(location.kilometersAway)} days to get to ${location.name}.`);
19   }
20}