Stay is a slim and effective module for the creation of dynamic xhr-driven web applications. It expects the server to be able to send a page's content as a simple JSON string in which the key names correspond with the IDs of the target DOM containers.
Download the minified library and include it in your project:
<script src="/js/stay.min.js"></script>You can also install this module from npm.
$ npm install @vanruesc/stayCreating an instance of Stay usually suffices.
import Stay from "@vanruesc/stay";
var stay;
try {
stay = new Stay();
} catch(error) {
// XHR not supported.
console.warn(error);
}You may also configure Stay's behaviour and take full control of the navigation flow.
import Stay from "@vanruesc/stay";
var stay;
try {
stay = new Stay({
// Logs to console by default
stderr: "myDomElement",
// Default is "/json"
infix: "/asyncRequests",
// Default is 60000ms, 0 means no timeout
timeoutPost: 0,
// Default is 5000ms
timeoutGet: 0,
// Default is true
autoUpdate: false
});
stay.addEventListener("navigate", function() {
console.log("Page navigation has started.");
startMyFancyLoadingAnimation();
});
stay.addEventListener("receive", function(event) {
maybeDoSomethingWithThe(event.response);
/* If autoUpdate is disabled, the programmer has to decide
* when to update the page content. The update() method MUST
* be called at some point to unlock the system!
*
* This event will always be dispatched. See the docs for
* payload information if you intend to process the server
* response.
*
* Please note: do not make your users wait artificially!
*/
stay.update(event.response);
});
stay.addEventListener("load", function() {
stopMyFancyLoadingAnimation();
console.log("The requested page has been loaded.");
});
} catch(error) {
console.warn(error);
}Every GET and POST endpoint needs to be available as a condensed JSON resource. This includes dynamically generated pages and error pages. Serving a JSON version of each resource should be seen as an additional feature and nothing more.
Stay is rather tolerant when it comes to different URI patterns, but a well-structured URI configuration is the foundation of a good web application. Take a look at some recommendations for good URI design if you haven't already! These guidelines are a good starting point.
The following example shows what's going on behind the scenes of Stay:
<a href="/foo/bar">Hyperlink</a>This link will internally be converted to:
"http[s]://www.your-domain.com[:port]/json/foo/bar"The modified URI won't be seen by the user and the infix can be freely chosen by you. If we assume that the original URI points to a simple HTML page which looks like this:
<html>
<head>
<meta charset="utf-8">
<title>Foo</title>
</head>
<body>
<div id="main">Bar!</div>
</body>
</html>then the JSON equivalent must look like this:
{
"meta": {
"title": "Foo"
},
"main": "Bar!"
}Stay would look at this JSON response and then try to replace the children of #main with the received
content which is a simple text node in this case, but could be any HTML content. The meta object's
title property is used to adjust the current page's title. Furthermore, the browser history will be
managed for you to support the back and forward browser controls.
Although the above example HTML is minimal, it highlights the main aspects of asynchronous web applications:
- More efficient bandwidth usage
- Better loading performance
- More control over the navigation process
- Consolidation of a main page structure
- Still highly customisable!
Stay detects external resources and doesn't touch them. The user will experience a synchronous navigation. Hyperlinks to internal resources such as images or executable files are problematic because they can't be identified as such by their URI alone. You may, however, define an arbitrary number of regular expressions to exclude specific URIs.
stay.exclusions.push(/\/nonJSON\//);When linking a resource that can't be represented in JSON format, you should consider moving it to a dedicated file server. Since Stay ignores external resources by default, the file would just open as expected.
Maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code.