How can I implement logging middleware in a Koa app?

How can I implement logging middleware in a Koa app?

You can create a logging middleware in Koa by using the 'koa-logger' package or by writing a custom middleware function.

Can you show me an example of a custom logging middleware?

Sure! Here's a simple example:

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

const logger = async (ctx, next) => {
    console.log(`${ctx.method} ${ctx.url}`);
    await next();
};

app.use(logger);
app.use(ctx => {
    ctx.body = 'Hello World';
});

app.listen(3000);

What if I want to log additional information like response time?

You can modify the middleware to calculate the response time like this:

const logger = async (ctx, next) => {
    const start = Date.now();
    await next();
    const ms = Date.now() - start;
    console.log(`${ctx.method} ${ctx.url} - ${ms}ms`);
};

Are there any other logging libraries you recommend?

Yes, you might want to check out 'winston' or 'bunyan' for more advanced logging features.