var isDone: boolean = false;

var height: number = 6;

var name: string = "bob";
name = ‘smith‘; 

var list:number[] = [1, 2, 3];

var list:Array<number> = [1, 2, 3];

enum Color {Red, Green, Blue};
var c: Color = Color.Green;

enum Color {Red = 1, Green, Blue};
var c: Color = Color.Green;

enum Color {Red = 1, Green = 2, Blue = 4};
var c: Color = Color.Green;

enum Color {Red = 1, Green, Blue};
var colorName: string = Color[2];

alert(colorName);

var notSure: any = 4;
notSure = "maybe a string instead";
notSure = false; // okay, definitely a boolean

var list:any[] = [1, true, "free"];

list[1] = 100;

function warnUser(): void {
    alert("This is my warning message");
}

function printLabel(labelledObj: {label: string}) {
  console.log(labelledObj.label);
}

var myObj = {size: 10, label: "Size 10 Object"};
printLabel(myObj);

interface LabelledValue {
  label: string;
}

function printLabel(labelledObj: LabelledValue) {
  console.log(labelledObj.label);
}

var myObj = {size: 10, label: "Size 10 Object"};
printLabel(myObj);

interface SquareConfig {
  color?: string;
  width?: number;
}

function createSquare(config: SquareConfig): {color: string; area: number} {
  var newSquare = {color: "white", area: 100};
  if (config.color) {
    newSquare.color = config.color;
  }
  if (config.width) {
    newSquare.area = config.width * config.width;
  }
  return newSquare;
}

var mySquare = createSquare({color: "black"});

interface SquareConfig {
  color?: string;
  width?: number;
}

function createSquare(config: SquareConfig): {color: string; area: number} {
  var newSquare = {color: "white", area: 100};
  if (config.color) {
    newSquare.color = config.collor;  // 这里编译器会进行类型检查
  }
  if (config.width) {
    newSquare.area = config.width * config.width;
  }
  return newSquare;
}

var mySquare = createSquare({color: "black"});  

interface SearchFunc {
  (source: string, subString: string): boolean;
}

var mySearch: SearchFunc;
mySearch = function(source: string, subString: string) {
  var result = source.search(subString);
  if (result == -1) {
    return false;
  }
  else {
    return true;
  }
}

var mySearch: SearchFunc;
mySearch = function(src: string, sub: string) {
  var result = src.search(sub);
  if (result == -1) {
    return false;
  }
  else {
    return true;
  }
}