ts 模块化

1. amd
2. commonjs
3. ……

// IShape.ts
export interface IShape {
  draw();
}

// Circle.ts
import shape = require("./IShape");
export class Circle implements shape.IShape {
   public draw() {
      console.log("Cirlce is drawn (external module)");
   }
}

// Triangle.ts
import shape = require("./IShape");
export class Triangle implements shape.IShape {
   public draw() {
      console.log("Triangle is drawn (external module)");
   }
}

// TestShape.ts
import shape = require("./IShape");
import circle = require("./Circle");
import triangle = require("./Triangle");
function drawAllShapes(shapeToDraw: shape.IShape) {
   shapeToDraw.draw();
}
drawAllShapes(new circle.Circle());
drawAllShapes(new triangle.Triangle());

tsc --module amd TestShape.ts

// IShape.js
define(["require", "exports"], function (require, exports) {
    "use strict";
    Object.defineProperty(exports, "__esModule", { value: true });
});

// Circle.js
define(["require", "exports"], function (require, exports) {
    "use strict";
    Object.defineProperty(exports, "__esModule", { value: true });
    exports.Circle = void 0;
    var Circle = /** @class */ (function () {
        function Circle() {
        }
        Circle.prototype.draw = function () {
            console.log("Cirlce is drawn (external module)");
        };
        return Circle;
    }());
    exports.Circle = Circle;
});

// Triangle.js
define(["require", "exports"], function (require, exports) {
    "use strict";
    Object.defineProperty(exports, "__esModule", { value: true });
    exports.Triangle = void 0;
    var Triangle = /** @class */ (function () {
        function Triangle() {
        }
        Triangle.prototype.draw = function () {
            console.log("Triangle is drawn (external module)");
        };
        return Triangle;
    }());
    exports.Triangle = Triangle;
});

// TestShape.js
define(["require", "exports", "./Circle", "./Triangle"], function (require, exports, circle, triangle) {
    "use strict";
    Object.defineProperty(exports, "__esModule", { value: true });
    function drawAllShapes(shapeToDraw) {
        shapeToDraw.draw();
    }
    drawAllShapes(new circle.Circle());
    drawAllShapes(new triangle.Triangle());
});

tsc --module commonjs TestShape.ts

// IShape.js
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });

// Circle.js
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Circle = void 0;
var Circle = /** @class */ (function () {
    function Circle() {
    }
    Circle.prototype.draw = function () {
        console.log("Cirlce is drawn (external module)");
    };
    return Circle;
}());
exports.Circle = Circle;

// Triangle.js
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Triangle = void 0;
var Triangle = /** @class */ (function () {
    function Triangle() {
    }
    Triangle.prototype.draw = function () {
        console.log("Triangle is drawn (external module)");
    };
    return Triangle;
}());
exports.Triangle = Triangle;

// TestShape.js
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
var circle = require("./Circle");
var triangle = require("./Triangle");
function drawAllShapes(shapeToDraw) {
    shapeToDraw.draw();
}
drawAllShapes(new circle.Circle());
drawAllShapes(new triangle.Triangle());

1. 声明文件以 .d.ts 为后缀
2. keyof 是 ts 中的一个操作符，用于获取一个类型的所有键作为字符串字面量类型的集合

interface Person {
  name: string;
  age: number;
}
type PersonKeys = keyof Person;  // type PersonKeys = "name" | "age"
function getPropertyValue(person: Person, key: PersonKeys): any {
  return person[key];
}
const bob: Person = {
  name: "Bob",
  age: 25
};
console.log(getPropertyValue(bob, "name")); // 输出: Bob
console.log(getPropertyValue(bob, "age"));  // 输出: 25
// 下面的代码将导致编译错误，因为 "address" 不是 Person 的一个键
// console.log(getPropertyValue(bob, "address"));
// 报错：类型“"address"”的参数不能赋给类型“keyof Person”的参数。ts(2345)