deployStack.js

const { config, STS } = require("aws-sdk");
const { execSync } = require("child_process");

const sts = new STS();

if (!config.region) {
  console.log("Set `$AWS_REGION` environment variable.");
  process.exit(1);
}

let Bucket;

sts
  .getCallerIdentity()
  .promise()
  .then(callerIdentity => {
    process.env["AWS_DEFAULT_REGION"] = config.region;

    Bucket = `cfn.${callerIdentity.Account}.${config.region}`;

    const packageCommand = [
      "aws",
      "cloudformation",
      "package",
      "--template-file",
      "template.cfn.json",
      "--s3-bucket",
      Bucket,
      "--output-template-file",
      ".cfn/packaged.json",
      "--use-json"
    ].join(" ");

    console.log(packageCommand);
    execSync(packageCommand, { stdio: "inherit" });

    const deployCommand = [
      "aws",
      "cloudformation",
      "deploy",
      "--template-file",
      ".cfn/packaged.json",
      "--capabilities",
      "CAPABILITY_IAM",
      "--stack-name",
      require("../package.json").name
    ].join(" ");

    console.log(deployCommand);
    execSync(deployCommand, { stdio: "inherit" });
  })
  .catch(error => {
    console.log(error);
    process.exit(1);
  });

prepareBucket.js

const { config, STS, S3 } = require("aws-sdk");

const sts = new STS();
const s3 = new S3();

if (!config.region) {
  console.log("Set `$AWS_REGION` environment variable.");
  process.exit(1);
}

let Bucket;

Promise.resolve()
  .then(() => {
    return sts.getCallerIdentity().promise();
  })
  .then(callerIdentity => {
    Bucket = `cfn.${callerIdentity.Account}.${config.region}`;

    return s3.getBucketLocation({ Bucket }).promise();
  })
  .then(getBucketLocationOutput => {
    const region = getBucketLocationOutput.LocationConstraint;

    if (
      region === config.region ||
      (config.region === "us-east-1" && region === "")
    ) {
      process.exit(0);
    } else {
      console.log(
        `Bucket \`${Bucket}\` is not in region \`${config.region}\`.`
      );
      process.exit(1);
    }
  })
  .catch(error => {
    if (error.name === "NoSuchBucket") {
      return s3
        .createBucket({
          Bucket,

          CreateBucketConfiguration:
            config.region === "us-east-1"
              ? undefined
              : {
                  LocationConstraint: config.region
                }
        })
        .promise();
    } else {
      console.log(error);
      process.exit(1);
    }
  })
  .then(createBucketOutput => {
    console.log("Bucket created", createBucketOutput);
  })
  .catch(error => {
    console.log(error);
  });