Load manager for asynchronous resource loading requests in complicated loading trees, with post processing of resources and caching.

This is useful for loading files that recursively trigger the loading of other files without having to manage promises or lots of callbacks explicitly. I originally used it for implementing project loading in a web integrated development environment.

The routines are:

• dataManager = new LoadManager()
• dataManager.fetch()
• dataManager.end()

No source dependencies. Requires ES5 for the Map class and for..of loop, which all modern browsers support. That is, doesn't work on Internet Explorer, but works on everything else including Safari, Firefox, Chrome, Edge, Opera, mobile versions, etc.

This implementation uses XMLHttpRequest internally. There is a newer browser API for making HTTP requests called Fetch (https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch) that uses Promises; it is more elegant in some ways but also more complicated because it relies on more language features. Since the current implementation is working fine, I don't intend to port to the Fetch API until some critical feature (such as the explicit headers or credentialing) is required.

Open Source under the BSD-2-Clause License:

Copyright 2018 Morgan McGuire, https://casual-effects.com

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.