delete object in S3

delete-aws-s3.js

var aws = require('aws-sdk');
var BUCKET = 'node-sdk-sample-7271';
aws.config.loadFromPath(require('path').join(__dirname, './aws-config.json'));
var s3 = new aws.S3();

var params = {
  Bucket: 'node-sdk-sample-7271', 
  Delete: { // required
    Objects: [ // required
      {
        Key: 'foo.jpg' // required
      },
      {
        Key: 'sample-image--10.jpg'
      }
    ],
  },
};

s3.deleteObjects(params, function(err, data) {
  if (err) console.log(err, err.stack); // an error occurred
  else     console.log(data);           // successful response
});

can delete by url?

Yes, you can through API Gateway and passing the parameters in query string