Rewrite on Lambda@Edge

index.js

'use strict';

exports.handler = (event, context, callback) => {
  const request = event.Records[0].cf.request;

  const regex = /.*\/$/;
  const result = request.uri.match(regex);

  if (result !== null) {
    request.uri += 'index.html';
  }

  callback(null, request);
}