node/tools/eslint-rules/require-buffer.js

'use strict';

const msg = 'Use const Buffer = require(\'buffer\').Buffer; ' +
            'at the beginning of this file';

module.exports = function(context) {
  return {
    'Program:exit': function() {
      context.getScope().through.forEach(function(ref) {
        if (ref.identifier.name === 'Buffer') {
            context.report(ref.identifier, msg);
        }
      });
    }
  }
}