Preloader

A library for loading common web assets

Usage

preloader

The preloader is capable of loading almost all types of files, if it does not understand a file type, it will attempt to load it as a basic xhr request. It extends the nodejs event emitter and uses the following events.

progress: Event Sends updates on loading progress to other part of application (loading ui) complete: Event Notifies loading completion to other part of application

Here is a common usage of the preloader.

var preloader = require('preloader');
var loader = preloader({
  xhrImages: false,
  crossOrigin:true
});
loader.on('progress',function(progress) {
  console.log(progress);
});
loader.on('complete',function() {
  var data = loader.get('site_data.json');
  console.log('all content loaded!');
});
loader.add('video1.mp4');
loader.add('test_image.jpg',{
  onComplete: function(content) {
    document.body.appendChild(loader.get('test_image.jpg'));
  }
});
loader.add('site_data.json');
loader.load();

new Preloader(options) / preloader(options)

This creates a new instance of the preloader on which on you use the following api. It is not a singleton and must be instantiated to use. The options object contains the following properties.

xhrImages Loads images via XHR and converts to a Blob instead of the image tag, default: false onComplete A function to attach to the complete event onProgress A function to attach to the progress event throttle A integer specifying maximum amount of connections at a time, 0 = infinite

add(url, options)

Generic asset loader function - determines loader to be used based on file-extension

url: String URL of asset options: Object Custom options to override the global options created at instantiation, can also pass in onComplete and onProgress to listen to the events on this particular item.

addImage(url ,options)

Load image - uses the LoaderImage loader

url: String URL of asset options: Object Custom options to override the global options created at instantiation, can also pass in onComplete and onProgress to listen to the events on this particular item.

addJSON(url, options)

Load JSON - uses the LoaderJSON loader

url: String URL of asset options: Object Custom options to override the global options created at instantiation, can also pass in onComplete and onProgress to listen to the events on this particular item.

addText(url, options)

Load text - uses the LoaderText loader

url: String URL of asset options: Object Custom options to override the global options created at instantiation, can also pass in onComplete and onProgress to listen to the events on this particular item.

addVideo(url, options)

Load video - uses the LoaderVideo loader

url: String URL of asset options: Object Custom options to override the global options created at instantiation, can also pass in onComplete and onProgress to listen to the events on this particular item.

addAudio(url, options)

Load audio - uses the LoaderAudio loader

url: String URL of asset options: Object Custom options to override the global options created at instantiation, can also pass in onComplete and onProgress to listen to the events on this particular item.

addImage(url, options)

Load image - uses the LoaderImage loader

url: String URL of asset options: Object Custom options to override the global options created at instantiation, can also pass in onComplete and onProgress to listen to the events on this particular item.

addFromLoaderType(url, loaderType, options)

Load asset using custom loader

url: String URL of asset loaderType: function Custom loader function options: Object Custom options to override the global options created at instantiation, can also pass in onComplete and onProgress to listen to the events on this particular item.

setPercentage(url, percentageOfLoad)

Sets percentage of total load for a given asset

url: String URL of asset percentageOfLoad: Number representing percentage of total load

load()

Begins loading process

stopLoad()

Stops loading process

get(url)

Retrieves loaded asset from loader

url: String URL of asset Returns: asset instance

reset()

Resets loading so you can reuse the preloader. does not remove cached loads so get() continues to function for all assets.

License

MIT, see LICENSE.md for details.