Scripts to import/export slack messages from/to a conversation or a channel

script-export.js

const fs = require("fs-extra");
const axios = require("axios");

const webhookUrl = "webhook_url_for_the_destination_conversation_or_channel_of_the_app_created_on_the_destination_slack_Workspace";

(async function () {
  const messages = fs.readJSONSync('./messages.json');
  for (const m of messages) {
//     const { text } = m;

//     if (!text) {
//       continue;
//     }

//     await axios.post(webhookUrl, { text });
    
    const { blocks } = m;

    await axios.post(webhookUrl, { attachments: [{ blocks }] });
  }
})().then(() => {
  console.log("Success");
})
  .catch((err) => {
    console.error(err.messages);
  })

script-import.js

const fs = require("fs-extra");
const axios = require("axios");

let cursor;
const limit = 1000;
const messages = [];

(async function () {
  while (1) {
    const { data } = await axios.get("https://slack.com/api/conversations.history", {
      params: {
        token: "<Access_token_for_an_app_created_on_the_source_slack_workspace_with_following_permissions>",
        channel: "<channle_id_or_conversation_id_i.e._2nd_part_on_the_url_https://app.slack.com/client/T0G78QW8L/D71PCNZLY>",
        cursor,
        inclusive: 1,
        limit,
        oldest: 0,
        pretty: 0
      }
    });

    if (!data.ok) {
      throw new Error(`Error: ${data}`);
    }

    messages.push(...data.messages);

    if (data.has_more) {
      cursor = data.response_metadata.next_cursor;
    } else {
      return;
    }
  }
})().then(() => {
  // const fMessages = messages.filter((m) => {
  //   if (m.subtype !== "bot_message") {
  //     return false;
  //   }

  //   const { blocks } = m;

  //   if (!blocks) {
  //     return false;
  //   }

  //   const dumbText = JSON.stringify(blocks).toLowerCase();
  //   if (dumbText.includes("some_filters")) {
  //     return false;
  //   }

  //   return true;
  // });
  const fMessages = messages;
  fs.writeJSONSync("./messages.json", fMessages.reverse(), { spaces: 2 });
})
  .catch((err) => {
    console.error(err);
  });

/*
* Permissions for the app created on the source slack workspace
* channels:history
* groups:history
* im:history
* mpim:history
*/