External Scripts

When developing bots, you may encounter cases where you wish to run code unrelated to your bot, sometimes even reference your client's instance.

Basic Scripts

By default, all .js and .ts files inside directories whose name doesn't start with a dot are watched and executed by the framework, reloading it each time the file gets saved, which means the following file will log Hello, world! each time it is saved.

console.log('Hello, world!')

console.log('Hello, world!')

But what if we wish to run some long running code, like a setInterval?

setInterval(() => {
  console.log('Hello, world!')
}, 1000)

setInterval(() => {
  console.log('Hello, world!')
}, 1000)

You can notice that it runs fine the first time, but once we save the file again, you will notice that the old timer keeps on going and stacks on each other!

Obviously that's not a good sign, so how do we stop the old timer when we save the file again?

Init Scripts

Thankfully, the framework handles a specially exported function called chooksOnLoad, which gets run each time the file is saved.

TIP

Init scripts can be async!

export function chooksOnLoad() {
  setInterval(() => {
    console.log('Hello, world!')
  }, 1000)
}

export function chooksOnLoad() {
  setInterval(() => {
    console.log('Hello, world!')
  }, 1000)
}

exports.chooksOnLoad = () => {
  setInterval(() => {
    console.log('Hello, world!')
  }, 1000)
}

Now when we restart our bot (to get rid of the old timers) and start it again we should see Hello, world! being printed into the console every second.

Okay it works, but when we save it again, our timers get stacked again! What gives?!

Well we didn't actually write anything that stops the timer when our file gets updated. So, how do we tell the framework to turn off the timer once a file update comes through?

Teardown Scripts

TIP

Like init scripts, teardown scripts can also be async!

To tell the framework what we want to do once the file gets updated, we just return another function, and it'll get executed once a change is detected.

export function chooksOnLoad() {
  console.log('Starting timer!')
  const interval = setInterval(() => {
    console.log('Hello, world!')
  }, 1000)

  return () => {
    console.log('Turning off timer!')
    clearInterval(interval)
  }
}

export function chooksOnLoad() {
  console.log('Starting timer!')
  const interval = setInterval(() => {
    console.log('Hello, world!')
  }, 1000)

  return () => {
    console.log('Turning off timer!')
    clearInterval(interval)
  }
}

exports.chooksOnLoad = () => {
  console.log('Starting timer!')
  const interval = setInterval(() => {
    console.log('Hello, world!')
  }, 1000)

  return () => {
    console.log('Turning off timer!')
    clearInterval(interval)
  }
}

For clarity's sake, we added some more logs to see when the file gets loaded and unloaded, and when we save the file (after restarting again to get rid of the old timers), the timers no longer stack and we can see when the file gets loaded and reloaded!

But now our script calls for reading some data off our Discord.JS client, and we also want to do some actual logging in our script, how do we gain access to these things in our scripts?

Script Context

Conveniently enough, the framework also passes a context object that contains the client along with a named logger that's special to our script!

To see what's available in our context object, we can use the Definition Function defineOnLoad.

import { defineOnLoad } from 'chooksie'

export const chooksOnLoad = defineOnLoad(ctx => {
  ctx.logger.info('Starting timer!')
  const interval = setInterval(() => {
    ctx.logger.info(`Our bot's ping is ${ctx.client.ws.ping}!`)
  }, 1000)

  return () => {
    ctx.logger.info('Turning off timer!')
    clearInterval(interval)
  }
})

import { defineOnLoad } from 'chooksie'

export const chooksOnLoad = defineOnLoad(ctx => {
  ctx.logger.info('Starting timer!')
  const interval = setInterval(() => {
    ctx.logger.info(`Our bot's ping is ${ctx.client.ws.ping}!`)
  }, 1000)

  return () => {
    ctx.logger.info('Turning off timer!')
    clearInterval(interval)
  }
})

const { defineOnLoad } = require('chooksie')

exports.chooksOnLoad = defineOnLoad(ctx => {
  ctx.logger.info('Starting timer!')
  const interval = setInterval(() => {
    ctx.logger.info(`Our bot's ping is ${ctx.client.ws.ping}!`)
  }, 1000)

  return () => {
    ctx.logger.info('Turning off timer!')
    clearInterval(interval)
  }
})

Now our script's logs are prettified and we can see which file the script is from, as well as print our client's ping!