How to do async calls in koa?

@elise_daugherty 

To make async calls in Koa, you can use async/await along with promises. Here's a step-by-step guide on how to do async calls in Koa:

1. Install Koa and any other necessary dependencies:

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npm install koa

1. Create a new Koa application:

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const Koa = require('koa');
const app = new Koa();

1. Define a route that requires an async call. This can be done using the .use() method:

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app.use(async (ctx, next) => {
  // Make an async call
  const result = await someAsyncFunction();
  
  // Do something with the result
  ctx.body = result;
});

1. Replace someAsyncFunction with your actual async function. This function should return a promise:

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function someAsyncFunction() {
  return new Promise((resolve, reject) => {
    // Do something async, e.g., make a database query
    setTimeout(() => {
      resolve('Async call completed');
    }, 2000);
  });
}

1. Start the Koa server:

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app.listen(3000, () => {
  console.log('Server listening on port 3000');
});

Now, when you make a request to http://localhost:3000, the async call will be made, and the result will be returned in the response body after it completes.