For example, When I use this function like this

// snippet-start:[s3.JavaScript.buckets.createBucket]
// Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set the region
AWS.config.update({region: 'REGION'});

// Create S3 service object
s3 = new AWS.S3({apiVersion: '2006-03-01'});

// Create the parameters for calling createBucket
var bucketParams = {
  Bucket : process.argv[2]
};

// call S3 to create the bucket
s3.createBucket(bucketParams, function(err, data) {
  if (err) {
    console.log("Error", err);
  } else {
    console.log("Success", data.Location);
  }
});

I want to see the code that implements the function. When I looked at the AWS SDK code, I couldn't go deeper than this.

Where can I see the code for the AWS SDK function?