collect.js

"use strict";

const {WebClient} = require("@slack/web-api");

const fs = require("fs").promises;
const web = new WebClient("xoxp-XXXXXXXXXXXXXX");

(async () => {
	while(true){
		const cursor = JSON.parse(await fs.readFile("cursor.json").catch(() => "null"));
		const data = JSON.parse(await fs.readFile("data.json").catch(() => "[]"));

		console.log(data.length, cursor);

		const res = await web.conversations.history({
			channel: "CXXXXXXXXXXXXX",
			limit: 1000,
			cursor,
		});

		await fs.writeFile("cursor.json", JSON.stringify(res.response_metadata.next_cursor));
		await fs.writeFile("data.json", JSON.stringify(data.concat(res.messages)));
	}
})();

count.js

"use strict";

const result = {};

require("./data.json").forEach(msg => {
	if(!msg.user){
		return;
	}
	msg.text.replace(/github\.com\/([-\w]+\/[-\w]+)/, (_, key) => {
		if(!(key in result)){
			result[key] = 0;
		}
		++result[key];
	});
});

Object.entries(result).sort(([, c1], [, c2]) => c2 - c1).forEach(([key, count]) => console.log(count, key));