gistfile1.txt

const fs = require("fs");
const AWS = require("aws-sdk");

const cognitoIdentityServiceProvider = new AWS.CognitoIdentityServiceProvider({ region: 'us-east-1' });

const styles = fs
  .readFileSync("styling.css", "utf8")
  .replace(/(\r\n\t|\n|\r\t)/gm, "") //remove newlines
  .replace("/*.+?*/"); // remove comments

  const image = fs.readFileSync('logo.png');


  const params = {
    UserPoolId: '<your-user-pool-id>',
    CSS: styles,
    ImageFile: Buffer.from(image)
  };
  
  cognitoIdentityServiceProvider.setUICustomization(params, (err, data) => {
    if (err) console.log(err, err.stack); // error 
    else console.log(`Successfully updated, new css version:  ${data.UICustomization.CSSVersion}`); // successful response
  });