Updated.

package.json

@@ -25,9 +25,13 @@
         "@types/reflect-metadata": "^0.1.0",
         "@types/uuid": "^3.4.5",
         "gulp": "^4.0.2",
+        "gulp-browserify": "^0.5.1",
+        "gulp-clean": "^0.4.0",
+        "gulp-concat": "^2.6.1",
+        "gulp-sourcemap": "^1.0.1",
         "gulp-sourcemaps": "^2.6.1",
         "gulp-typescript": "^5.0.1",
-        "gulp-uglify": "^3.0.0",
+        "gulp-uglify": "^3.0.2",
         "live-server": "^1.2.0",
         "typescript": "^3.6.4"
     },

src/Circle.ts

@@ -0,0 +1,8 @@
+/// <reference path="IShape.ts" />
+namespace Drawing {
+    export class Circle implements IShape {
+        public draw(): void {
+            console.log("Circle is drawn.");
+        }
+    }
+}

src/IShape.ts

@@ -0,0 +1,5 @@
+namespace Drawing {
+    export interface IShape {
+        draw(): void;
+    }
+}

src/TestShape.ts

@@ -0,0 +1,10 @@
+/// <reference path="IShape.ts" />
+/// <reference path="Circle.ts" />
+/// <reference path="Triangle.ts" />
+
+function drawAllShapes(shape: Drawing.IShape) {
+    shape.draw();
+}
+
+drawAllShapes(new Drawing.Circle());
+drawAllShapes(new Drawing.Triangle());

src/Triangle.ts

@@ -0,0 +1,8 @@
+/// <reference path="IShape.ts" />
+namespace Drawing {
+    export class Triangle implements IShape {
+        public draw(): void{
+            console.log("Triangle is drawn.");
+        }
+    }
+}

src/functions.ts

@@ -0,0 +1,68 @@
+function push<T>(array: Array<T>, ...items: Array<T>) {
+    items.forEach(i => {
+        array.push(i);
+    });
+}
+
+let arrayA: Array<string> = [];
+push(arrayA, '1', '2', '3', '7');
+console.log(arrayA);
+// [ 1, 2, 3, 'test' ]
+
+// 为了精准表达输入为数字，输出也是数字；输入为字符串，输出也是字符串
+function reverse(x: number): number;
+function reverse(x: string): string;
+
+function reverse(x: number | string): number | string {
+    if (typeof x === 'number') {
+        return Number(x.toString().split('').reverse().join(''));
+    } else if (typeof x === 'string') {
+        return x.split('').reverse().join('');
+    }
+}
+
+console.log(reverse('This is a test.'));
+console.log(reverse(2742312534));
+
+interface SearchFunc {
+    (source: string, subString?: string): boolean;
+}
+
+let mySearch: SearchFunc;
+mySearch = function(source: string, subString: string = 'as') {
+    return source.search(subString) !== -1;
+}
+console.log(mySearch('This is a test.'));
+
+function buildName(firstName: string, lastName: string = 'Tom') {
+    return `${firstName} ${lastName}`;
+}
+console.log(buildName('John'));
+
+// Type Assertion
+function getLength(a: string | number): number{
+    if((<string>a).length){
+        return (<string>a).length;
+    } else {
+        return a.toString().length;
+    }
+}
+console.log(getLength('This is a test.'));
+console.log(getLength(988123035235));
+
+function toBoolean(b: string | number): boolean {
+    if((<string>b).length > 0) {
+        return true;
+    } else
+    if(Math.abs(b as number) > 0){
+        return true;
+    } else return false;
+
+
+}
+
+console.log(toBoolean(-1));
+console.log(toBoolean(0));
+
+console.log(toBoolean('This is a test.'));
+console.log(toBoolean(''));