Promise Error Handling

promise-error-handling.js

## How to run
#
# npm run main /invalid
#

const get = url => {
  if (url.indexOf('/invalid') >= 0) {
    return Promise.reject({
      url,
      error: 'error message',
      response: {
        status: 400
      }
    });
  }

  return Promise.resolve({
    url,
    status: 200,
    body: 'output'
  });
};

const getSwallowerInterceptor = url => {
  return get(url)
    .then(output => {
      console.log('GET then');
      return output;
    })
    .catch(error => {
      console.error('GET catch');
      return error;
    });
};
const getThrowerInterceptor = url => {
  return get(url)
    .then(output => {
      console.log('GET then');
      return output;
    })
    .catch(error => {
      console.error('GET catch');
      return Promise.reject(error);
    });
};
const getNoCatchHandlingInterceptor = url => {
  return get(url)
    .then(output => {
      console.log('GET then');
      return output;
    });
};

const urlParam = process.argv[2];
getSwallowerInterceptor(urlParam)
  .then(response => console.log('GET[swallower] then', response))
  .catch(error => console.error('GET[swallower] catch', error));

getThrowerInterceptor(urlParam)
  .then(response => console.log('GET[thrower] then', response))
  .catch(error => console.error('GET[thrower] catch', error));

getNoCatchHandlingInterceptor(urlParam)
  .then(response => console.log('GET[noCatch] then', response))
  .catch(error => console.error('GET[noCatch] catch', error));

/*
GET catch
GET catch
GET[swallower] then { url: '/invalid',
  error: 'error message',
  response: { status: 400 } }
GET[noCatch] catch { url: '/invalid',
  error: 'error message',
  response: { status: 400 } }
GET[thrower] catch { url: '/invalid',
  error: 'error message',
  response: { status: 400 } }
*/