alite

Alite

A simple, tiny promise-based AJAX library.

• Zero dependencies
• Roughly 500 bytes minified and gzipped

Usage

Create a new instance of Alite:

var alite = Alite();

Ajax methods

There are several methods, each with an identical signature: put, post, patch, get, delete, and ajax.

Each of these takes a single argument, which is an object of the following shape:

{
  // Required: the URL to send/receive from
  url: '/api/foo/bar',

  // Optional: the object to send as JSON, or raw if the raw flag is set
  data: { foo: 'bar' },

  // Optional: A flag indicating whether or not this is a raw request
  // (by default, this is false, and data is turned into a JSON string)
  raw: false,

  // Optional: an object containing the HTTP headers to set
  headers: {
    'Authorization': 'Basic ' + btoa(username + ':' + password)
  },

  // Optional: a function to be called before the AJAX request is sent
  ajaxStart: function (xhr) {
    // ...
  }
}

Some examples follow:

alite.get({ url: '/api/foo' });

alite.delete({ url: '/api/foo/1' });

alite.patch({
  url: '/api/foo/1',
  data: { name: 'Joe', age: 32 }
});

alite.put({
  url: '/api/foo/1',
  data: { name: 'Joe', age: 32 }
});

alite.post({
  url: '/api/foo',
  data: { name: 'Joe', age: 32 }
});

alite.ajax({
  url: '/api/foo',
  data: { name: 'Joe', age: 32 },
  method: 'POST'
});

Promises

Each of these methods returns a promise, and so is generally called like this:

alite.get({ url: 'https://api.github.com/users' })
  .then(function (result) {
    // Result is the deserialized JSON object/array that came back from the server
    console.log(result);
  })
  .catch(function (err) {
    // err is the deserialzed JSON object/array that was returned from the server
    console.log(err);
  });

The promise object has a non-standard property attached to it: xhr which can be accessed inside then/catch via this.xhr.

alite.delete('users/24')
  .then(function (result) {
    console.log(result); // The JSON object received
    console.log(this.xhr.getResponseHeader('Server')); // Get the XHR object from the promise
  });

Example file upload

The following code is taken from a production app that uploads files to S3:

// File is a file object obtained from an input[type=file] element
// presigned is an object representing AWS S3 presigned URL info...
function upload(file, presigned) {
  var alite = Alite();
  var data = new FormData();

  data.append('utf8', '✓');
  data.append('Content-Type', file.type);
  data.append('Content-Disposition', 'attachment; filename = "${filename}"');
  data.append('key', presigned.fullKey);
  data.append('AWSAccessKeyId', presigned.awsAccessKeyId);
  data.append('acl', presigned.acl);
  data.append('policy', presigned.policy);
  data.append('signature', presigned.signature);
  data.append('file', file);

  return alite.post({
    url: presigned.url,
    data: data,
    raw: true, // This isn't going to be a JSON request
    ajaxStart: function (xhr) {
      xhr.upload.addEventListener('progress', function (e) {
        updateProgressBar(Math.ceil((e.loaded / e.total) * 100));
      }, false);
    }
  });
}

Global AJAX notifications: ajaxStart/ajaxStop

The Alite object has two properties which you can set in order to receive notifications when an ajax request starts or completes:

var alite = Alite();

// xhr is the raw XMLHttpRequest object
// opts is the argument that was passed to the Alite ajax method
//   that triggered this request.
alite.ajaxStart = function (xhr, opts) {
  // Pass the CSRF token along with the request...
  xhr.setRequestHeader('X-CSRF-Token', document.querySelector('meta[name="csrf-token"]').getAttribute('content'));
};

alite.ajaxStop = function (xhr, opts) {
  // This runs whenever an AJAX request has completed (success or error)
};

Assumptions

If raw is not specified or is false, data is sent as JSON and is automatically serialized for you.

Alite requires Promise support. In older browsers, Promises can be shimmed easily enough with something like Plite.

Alite currently has a naive method of detecting if a response is JSON... If it starts with { or [, then the response is considered JSON.

Installing

Download and include alite.min.js

Or install using NPM:

npm install alite

Or install using Bower:

bower install alite

License MIT

Copyright (c) 2015 Chris Davies

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.