plugins-use-demo.js

plugins.use(async (next) => {
  console.log('a');
  await next();
  console.log('b')
})

plugins.use(async (next) => {
  console.log('c');
  await next();
  console.log('d')
})

plugins.run(() => {
  console.log('done')
});
// output a c d b 

Plugins.js

//
// Simple plugins mode in koajs use JavaScript async await
// https://github.com/senchalabs/connect/blob/master/index.js
//
const plugins = {
  stack: [],
  use: (plugin) => {
    plugins.stack.push(plugin);
  },
  run: async (done) => {
    const { stack } = plugins;
    let index = 0;
    const next = async () => {
      const plugin = stack[index++];
      if (!plugin) {
        return Promise.resolve();
      }
      await plugin(next);
    }
    await next();
    done && done()
  }
}