index.js

'use strict';

var GitHub = require('github-api');
var fetch = require('node-fetch');
var exec = require('child_process').exec;

const gh = new GitHub({ token: 'MY_TOKEN' });
const org = gh.getOrganization('MY_ORG');

fetch('https://api.bitbucket.org/2.0/teams/MY_ORG/repositories')
    .then(data => data.json())
    .then(body => {
        body.values.forEach(value => {
            let cloneLink = value.links.clone.filter(link => link.name === 'https')[0]
            migrate(value.name, cloneLink.href);
        })
    });

function migrate(name, remoteUrl) {
    console.log('migrate: ' + remoteUrl);

    doExec(`git clone ${remoteUrl} ${name}`)
        .then(() => org.createRepo({
            name: name,
            private: false,
            team_id: MY_TEAM_ID
        }))
        .then(resp => doExec(`git --git-dir ${name}/.git remote set-url origin ${resp.data.clone_url}`))
        .then(resp => doExec(`git --git-dir ${name}/.git push --all`))
        .then(resp => doExec(`git --git-dir ${name}/.git push --tags`))
        .catch(console.warn);
}

function doExec(command) {
    console.log('exec: ' + command);

    return new Promise((resolve, reject) => {
        exec(command, (err, stdout, stderr) => {
            if (err) {
                reject(err)
                return;
            }
            resolve();
        });
    });
}

package.json

{
  "name": "bitbucket-to-github-migrator",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "git": "^0.1.5",
    "github-api": "^2.3.0",
    "node-fetch": "^1.5.3"
  }
}