Express的app对象

通过ts的特性，不断溯源app对象

import express from 'express';
const app = express();

ctrl+点击 express()

core.Express

ctrl+点击 core.Express

Application

ctrl+点击 Application

export interface Application extends EventEmitter, IRouter, Express.Application {
    (req: Request | http.IncomingMessage, res: Response | http.ServerResponse): any;
    init(): void;
    defaultConfiguration(): void;
    engine(ext: string, fn: (path: string, options: object, callback: (e: any, rendered?: string) => void) => void): this;
    set(setting: string, val: any): this;
    get: ((name: string) => any) & IRouterMatcher<this>;
    param(name: string | string[], handler: RequestParamHandler): this;
    param(callback: (name: string, matcher: RegExp) => RequestParamHandler): this;
    path(): string;
    enabled(setting: string): boolean;
    disabled(setting: string): boolean;
    /** Enable `setting`. */
    enable(setting: string): this;
    /** Disable `setting`. */
    disable(setting: string): this;
    render(name: string, options?: object, callback?: (err: Error, html: string) => void): void;
    render(name: string, callback: (err: Error, html: string) => void): void;
    listen(port: number, hostname: string, backlog: number, callback?: () => void): http.Server;
    listen(port: number, hostname: string, callback?: () => void): http.Server;
    listen(port: number, callback?: () => void): http.Server;
    listen(callback?: () => void): http.Server;
    listen(path: string, callback?: () => void): http.Server;
    listen(handle: any, listeningListener?: () => void): http.Server;
    router: string;
    settings: any;
    resource: any;
    map: any;
    locals: Record<string, any>;
    routes: any;
    _router: any;
    use: ApplicationRequestHandler<this>;
    on: (event: string, callback: (parent: Application) => void) => this;
    mountpath: string | string[];
}
export interface Express extends Application {
    request: Request;
    response: Response;
}

可以看到有init，set，get，listen等方法。 目前用到了get和listen

EventEmitter

而且这个Application是继承自EventEmitter和IRouter的
EventEmitter是说明它是一个流 可以执行事件监听

IRouter

Ctrl 点击IRouter看看他是什么东西
它里面有很多http的动词

小结

以上就是app的继承关系

• Express extends Application
• Application extends EventEmitter , IRouter…
• 其中IRouter包含了get/post/put等方法

基本上可以看到app的全貌了，ts就跟文档一样。