Koa 开发服务器和热更实现

[nuintun]

dev.js

/**
 * @module dev
 * @license MIT
 * @author nuintun
 * @author yiminghe
 * @description Webpack dev middleware for koa2
 * @see https://github.com/yiminghe/koa-webpack-dev-middleware/blob/2.x/src/index.js
 */

'use strict';

const expressMiddleware = require('webpack-dev-middleware');

module.exports = (compiler, options) => {
  const middleware = expressMiddleware(compiler, options);

  const devMiddleware = async (ctx, next) => {
    ctx.remove('Content-Type');

    await middleware(
      ctx.request,
      {
        locals: ctx.state,
        status(statusCode) {
          ctx.status = statusCode;
        },
        set(field, value) {
          ctx.response.set(field, value);
        },
        get(field) {
          return ctx.response.get(field);
        },
        send(content) {
          ctx.body = content;
        }
      },
      next
    );
  };

  Object.keys(middleware).forEach(key => (devMiddleware[key] = middleware[key]));

  return devMiddleware;
};

hot.js

/**
 * @module hot
 * @license MIT
 * @author nuintun
 * @author kimjuny
 * @description Webpack hot middleware for koa2
 * @see https://github.com/kimjuny/koa-webpack-server/blob/master/src/hot.js
 */

'use strict';

const { PassThrough } = require('stream');
const expressMiddleware = require('webpack-hot-middleware');

module.exports = (compiler, options) => {
  const middleware = expressMiddleware(compiler, options);

  const hotMiddleware = async (ctx, next) => {
    const stream = new PassThrough();

    ctx.body = stream;

    const locals = ctx.state;
    const end = stream.end.bind(stream);
    const write = stream.write.bind(stream);
    const writeHead = (status, headers) => {
      ctx.status = status;

      ctx.set(headers);
    };

    await middleware(ctx.req, { locals, writeHead, write, end }, next);
  };

  Object.keys(middleware).forEach(key => (hotMiddleware[key] = middleware[key]));

  return hotMiddleware;
};