instagram.js

var Nightmare  = require('nightmare');

var username = '';
var password = '';

new Nightmare()

  .viewport(800, 600)
  .goto('https://instagram.com/accounts/login/')
  .wait()

  .type('[name=username]', username)
  .type('[name=password]', password)
  .click('.-cx-PRIVATE-LoginForm__loginButton')

  .wait()

  .click('.-cx-PRIVATE-PostInfo__likeButton')

  .screenshot('./insta.png')

  .run();