var Converter = require('api-spec-converter');

Converter.convert({
  from: 'swagger_1',
  to: 'swagger_2',
  source: 'https://api.gettyimages.com/swagger/api-docs',
}, function(err, converted) {
  console.log(converted.stringify());
  // For yaml and/or OpenApi field order output replace above line
  // with an options object like below
  //   var  options = {syntax: 'yaml', order: 'openapi'}
  //   console.log(converted.stringify(options));
})

var Converter = require('api-spec-converter');

Converter.convert({
  from: 'swagger_1',
  to: 'swagger_2',
  source: 'https://api.gettyimages.com/swagger/api-docs',
})
.then(function(converted) {
  console.log(converted.stringify());
});

var Converter = require('api-spec-converter');
Converter.convert({
  from: 'swagger_1',
  to: 'swagger_2',
  source: 'https://api.gettyimages.com/swagger/api-docs',
})
  .then(function(converted) {
    // [Optional] Fill missing fields with dummy values
    converted.fillMissing();

    // [Optional] Validate converted spec
    return converted.validate()
      .then(function (result) {
        if (result.errors)
          return console.error(JSON.stringify(errors, null, 2));
        if (result.warnings)
          return console.error(JSON.stringify(warnings, null, 2));

        fs.writeFileSync('swagger2.json', converted.stringify());
      });
  });

<script src="node_modules/api-spec-converter/dist/api-spec-converter.js"></script>
APISpecConverter.convert(...)