koa基础

const koa = require("koa");
const app = new koa();

app.use(async ctx => {
  ctx.body = "Hello koa2";
});

app.listen(8080);

const Koa = require("koa");
const Router = require("koa-router");

const app = new Koa();
const router = new Router();

router.get("/", (ctx, next) => {
  ctx.body = "Hello Koa";
});

router.get("/news", (ctx, next) => {
  ctx.body = "Hello news";
});

app.use(router.routes());
app.use(router.allowedMethods());

app.listen(8080, () => {
  console.log("starting at port 8080");
});

• 链式写法

const Koa = require("koa");
const Router = require("koa-router");

const app = new Koa();
const router = new Router();

router
  .get("/", async (ctx, next) => {
    ctx.body = "Hello Koa";
  })
  .get("/news", async (ctx, next) => {
    ctx.body = "Hello news";
  });

app.use(router.routes()).use(router.allowedMethods());

app.listen(8080, () => {
  console.log("starting at port 8080");
});

• 简化写法&注释

const Koa = require("koa");
const router = require("koa-router")();

const app = new Koa();

router
  .get("/", async ctx => {
    ctx.body = "home";
  })
  .get("/news", async ctx => {
    ctx.body = "news";
  });

app
  .use(router.routes()) // 启动路由
  .use(router.allowedMethods());//有一段比较操蛋的功能，先不管他

app.listen(8080);