How do I test if a bucket exists on AWS S3

You can use the following code:

// import or require aws-sdk as AWS
// const AWS = require('aws-sdk');

const checkBucketExists = async bucket => { 
  const s3 = new AWS.S3();
  const options = {
    Bucket: bucket,
  };
  try {
    await s3.headBucket(options).promise();
    return true;
  } catch (error) {
    if (error.statusCode === 404) {
      return false;
    }
    throw error;
  }
};

The important thing is to realize that the error statusCode will be 404 if the bucket does not exist.

To test if a bucket exists, you check the statusCode attribute from your createBucket callback method. If it is 409, then it has been created before. I hope this is clear enough?

const ID = ''//Your access key id
const SECRET = ''//Your AWS secret access key

const BUCKET_NAME = ''//Put your bucket name here

const s3 = new AWS.S3({
    accessKeyId: ID,
    secretAccessKey: SECRET
})

const params = {
    Bucket: BUCKET_NAME,
    CreateBucketConfiguration: {
        // Set your region here
        LocationConstraint: "eu-west-1"
    }
}
s3.createBucket(params, function(err, data) {
   if (err && err.statusCode == 409){
    console.log("Bucket has been created already");
   }else{
       console.log('Bucket Created Successfully', data.Location)
   }
})

Looks like after this change from aws-sdk v2 to v3 you can't do it with headBucket().

For those who are using v3 you could give this a shot:

const { S3Client, HeadBucketCommand } = require('@aws-sdk/client-s3');

const checkBucketExists = async (bucket) => {
    const client = new S3Client();
    const options = {
        Bucket: bucket,
    };

    try {
        await client.send(new HeadBucketCommand(options));
        return true;
    } catch (error) {
        if (error["$metadata"].httpStatusCode === 404) {
            return false;
        }
        throw error;
    }
}