---
title: "Adding context"
summary: "All listeners have access to a context object, which can be used to enrich requests with additional information. For example, perhaps you want to add user information from a third party system or add temporary state for the next middleware in the chain."
url: "https://docs.slack.dev/tools/bolt-js/concepts/context"
type: "guide"
---

Source: https://docs.slack.dev/tools/bolt-js/concepts/context

# Adding context

All listeners have access to a `context` object, which can be used to enrich requests with additional information. For example, perhaps you want to add user information from a third party system or add temporary state for the next middleware in the chain.

`context` is just an object, so you can add to it by setting it to a modified version of itself.

## Example {#example}

```
async function addTimezoneContext({ payload, client, context, next }) {  const user = await client.users.info({    user: payload.user_id,    include_locale: true  });  // Add user's timezone context  context.tz_offset = user.tz_offset;  // Pass control to the next middleware function  await next();}app.command('/request', addTimezoneContext, async ({ command, ack, client, context, logger }) => {  // Acknowledge command request  await ack();  // Get local hour of request  const localHour = (Date.UTC(2020, 3, 31) + context.tz_offset).getHours();  // Request channel ID  const requestChannel = 'C12345';  const requestText = `:large_blue_circle: *New request from <@${command.user_id}>*: ${command.text}`;  // If request not in between 9AM and 5PM, send request tomorrow  if (localHour > 17 || localHour < 9) {    // Assume function exists to get local tomorrow 9AM from offset    const localTomorrow = getLocalTomorrow(context.tz_offset);    try {      // Schedule message      const result = await client.chat.scheduleMessage({        channel: requestChannel,        text: requestText,        post_at: localTomorrow      });    }    catch (error) {      logger.error(error);    }  } else {    try {      // Post now      const result = await client.chat.postMessage({        channel: requestChannel,        text: requestText      });    } catch (error) {      logger.error(error);    }  }});
```