let color: string = "rebeccapurple";
let myNum: number = 42;
let truth: boolean = true;

//built in objects
let now: Date = new Date()
//arrays
let colors: string[] = ["red", "green", "blue"];
let myNums: number[] = [1, 2, 3];
let truths: boolean[] = [true, false, true];
//classes
class Car {

}
let car: Car = new Car();
//object literal
let cartesianPoint: {x: number; y: number, z: number} = {
  a: 10, //will also produce an err; should be "x" instead of "a"
  y: 20,
  z: "it's pronounced zed!" //this produces an err; should be a number not a string
//functions
const logNumber: (num: number) => void = num => {
  console.log(num);
};
let color = "red"; //TS infers the value on a single line; multiple lines have ": any"

//AVOIDE 'any' AT ALL COSTS

//When to use type annotation
//1)Functions that return the any type
const json = '{"x": 10, "y": 20}';
const coordinates: { x: number; y: number } = JSON.parse(json);
console.log(coordinates);
//JSON.parse() is one of many that returns type "any"
//2)When we declare a variable on one line and initialize it later
let nums = [1, 2, 3, 4, 5];
let foundNum: boolean;
for (let i = 0; i < nums.length; i++) {
  if (nums[i] === 3) {
    foundNum = true;
  }
}
//3)When inference doesn't work
//wanted numAboveZero to default as false then change to a num above 0;
let nums = [-10,-1,12];
let numAboveZero: boolean | number = false;

for (let i = 0; i < nums.length; i++) {
  if (nums[i] > 0) numAboveZero = nums[i];
}

//ensures the inputs are numbers
const add = (a: number, b: number): number => {
  //ensures the return value exists and is a number. won't allow for void return values that just have side effects
  return a + b;
};

console.log(add(5, 6)); //11

const profile = {
  name: "alex",
  age: 20,
  coords: {
    lat: 0,
    long: 15,
  },
  setAge(age: number): void {
    this.age = age;
  },
};

const {
  age,
  name,
  coords: { lat, long },
}: {
  age: number;
  name: string;
  coords: { lat: number; long: number };
} = profile;

interface Vehicle {
  name: string;
  year: Date;
  broken: boolean;
  summary(): string;
}

const oldCivic = {
  name: "civic",
  year: new Date("10-10-2000"),
  broken: true,
  summary() {
    return `name: ${this.name}\nyear: ${this.year}\nbroken: ${
      this.broken ? "yes" : "no"
    }`;
  },
};

const printVehicle = (vehicle: Vehicle): void => {
  console.log(vehicle.summary());
};

printVehicle(oldCivic);