jd-style-update

Jimdo Style Update

Updating service for CSS - Ensuring that style-critical function calls are not executed while CSS is being loaded.

Install

bower install jd-style-update

angular.module('myApp', ['jd-style-update'])

The Problem

When the following style tag is added to a page

<style type="text/css">
@import url('http://my.webfont.provider.example.org/fonts.css');
body {
    background: fuchsia;
}
</style> 

It's not possible to get a reliable JS callback when the style is actually applied because the webfont request will block CSS rendering and will not trigger any JS callbacks when done.

Solution

We add a custom CSS rule to each style update

<style type="text/css">
@import url('http://my.webfont.provider.example.org/fonts.css');
/* ... */
.jd-style-update-loading-123456789 {
    content: "loaded";
}
</style> 

and a Marker element to the dom

<div class="jd-style-update-loading-123456789"></div>

then each style-crytical function is passed into a queue that is aware of the current css loading state

// pseudo code
queue.push(function() { /* ... */ });

and then we check for this rule to be applied

// pseudo code
while ($marker.css('content') !== 'loaded') {
    wait();
}

and run the queue

queue.run();

Usage

jdStyleUpdater

angular.module('myApp').run(function(jdStyleUpdater) {
    jdStyleUpdater.update([
        '@import url("http://my.webfont.provider.example.org/fonts.css");',
        'body {',
        '	background: fuchsia;',
        '}'
    ].join('')).then(function() {
        expect(angular.element(document.body)
            .css('background')).toBe('fuchsia');
    });
 
    // get promise without triggering an update
    jdStyleUpdater.ready().then(successCallback).catch(errorCallback);
});

jdStyleSafe

angular.module('myApp').run(function(jdStyleSafe) {
    // callbacks will be executed whenever there 
    // is no jdStyleUpdater.update in process 
    jdStyleSafe.apply(myCallback, ['foo', 'bar']);
    jdStyleSafe.call(myOtherCallback, 'foo', 'bar');
});

Configuration

angular.module('myApp').
    // base class that is applied to the marker element
    .constant('jdsuApplicatorMarkerClass', 'jd-style-update-loading-');
    // class for the <style> element  
    .constant('jdsuStyleTagClass', 'jd-style-update-style');
    // the css property that is used to check if the style is applied
    .constant('jdsuApplicatorLoadingProperty', 'content');
    // the properties value that is used to check if the style is applied
    .constant('jdsuApplicatorLoadingValue', 'loaded');
    // amount of time after we stop looking for the style and fail
    .constant('jdsuApplicatorTimeout', 2000);
    // amount of time between update checks
    .constant('jdsuApplicatorCheckInterval', 200);

Contribute

Initialize tooling

npm install

Grunt Tasks

• grunt: Execute tests
• grunt coverage: Serve coverage report on port 7000
• grunt test: Just test
• grunt test:e2e: Just test end to end
• grunt test:unit: Just test unit
• grunt tdd: Watch source and test files and run tests
• grunt tdd:e2e: Watch and test just end to end
• grunt tdd:unit: Watch and test just unit
• grunt build: Just build
• grunt release: Test, build, bump patch version, commit, add version tag and push

test tasks have a --browsers option to specify the browsers you want to use

See grunt-angular-toolbox for details

LICENSE

The MIT License

Copyright (c) 2015 Jimdo GmbH http://jimdo.com

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.