Switch - Fetcher

Wrap the Fetch API with convenience methods.

Methods get, send, form returns a promise that will resolve or reject with an object containing the data of the response when possible.

The structure of the response's object uses the same structure the response interface properties of a fetch request.

Structure of a fetch response object:

{
    data,
    headers,
    ok,
    redirected,
    status,
    statusText,
    type,
    url
  }

The headers entry returns an object containing the headers received by the server. You can access them by using their names like headers[ 'content-type' ]. Headers are in lowercase.

Depending of the response's Content-Type header the data structure of returned value will be different:

• application/json - a JSON object
• multipart/form-data - a FormData object
• application/octet-stream - a Blob

Any other Content-Type will be returned as a USVString

Unlike the Fetch API, when Response.ok is falsy the returned promise is rejected, allowing you to catch and treat differently the error cases.

Example of 404 rejection:

{
  headers: {
    "content-type": "text/plain"
  },
  redirected: false,
  ok : false,
  status: 404,
  statusText: "Not Found",
  type: "basic",
  url: "https://localhost:3000/fetch"
}

If the fetch request times out or the fetched url is unavailable the returned object will only contain status, statusText and url since the server is not involved in the request.

When the request times out the status code will be 599 otherwise it will be 0.

Parameters

Default parameters can be changed using fetch.config = {};

Default parameters

• headers - default headers to send. Any headers set when making a request will overide the default headers
• params - standard fetch api request properties minus the header entry - defaults to { credentials: 'same-origin' }
• timeout - duration in milliseconds before the request is considered timed out - defaults to 30000

Methods

.get( url, parameters, fetchOptions )

Execute a GET request to the url using the parameters provided.

Parameters

Parameters are any parameter provided by the fetch API.

A data object is avalaible to pass the query string.

fetchOptions

Fetcher specific options for the current request (optional).

• parse - if false, the request will not be parsed by fetcher and will return the fetch response object (defaults to true)
• timeout - specific timeout for the current request (in milliseconds)

Creating a GET fetch

// create a 'GET' request to "/search?term=fetch"
fetchy.get( '/search', {
  data: {
    term: 'fetch'
  }
});

.send( url, parameters, fetchOptions )

Send data to the url using the parameters provided. Method defaults to POST.

Parameters

Parameters are any parameter provided by the fetch API.

A data object is avalaible to pass a JSON, a Blob or a FormData object.

In order to POST a FormData object, the request's Content-Type must be set to multipart/form-data.

fetchOptions

Fetcher specific options for the current request (optional).

• parse - if false, the request will not be parsed by fetcher and will return the fetch response object (defaults to true)
• timeout - specific timeout for the current request (in milliseconds)

.form( HTMLFormElement, parameters, fetchOptions )

Shortcut to create a fetch request based on a form element. The request endpoint and method are based on the form's action and method attributes. Entries in the parameters object overwrite the form's attribute when fetching.

Non-strings fields value will be ignored when the from's method is set to GET.

A FormData object will be sent only when a non-string field value is found. By default the form's data object is a JSON object.

Parameters

Parameters are any parameter provided by the fetch API.

fetchOptions

Fetcher specific options for the current request (optional).

• parse - if false, the request will not be parsed by fetcher and will return the fetch response object (defaults to true)
• timeout - specific timeout for the current request (in milliseconds)