README

grunt-css-preload

Automatically add an image preload rule to your stylesheets.

Getting Started

This plugin requires Grunt ~0.4.5

If you haven't used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

npm install grunt-css-preload --save-dev

Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:

grunt.loadNpmTasks('grunt-css-preload');

The "csspreload" task

Overview

This task scans your stylesheet AST for any declared URL, and preload them using the display:none trick on a typically unused but always present selector (by default, body:after).

In your project's Gruntfile, add a section named csspreload to the data object passed into grunt.initConfig().

grunt.initConfig({
  csspreload: {
    options: {
      // Task-specific options go here.
    },
    your_target: {
      // Target-specific file lists and/or options go here.
    },
  },
});

Options

options.extraUrls

Type: Array<String> Default value: [ ]

An array of any extra file that you wish to include in the preload entry.

options.extensions

Type: Array<String> Default value: [ '.png', '.jpg', '.jpeg', '.bmp', '.gif' ]

An array of the extensions that should be considered for preload.

options.selector

Type: String Default value: 'body:after'

The selector that should host the preloading rule.

options.extendSource

Type: Boolean Default value: true

If true, the output will contain the original concatenated source code before the preloading rule. Otherwise, the output will only contain the preloading rule.

Note that this plugin doesn't check to see if a preloading rule already exists - so multiple invocations of the csspreload task with the extendSource option set might make the file grow linearly.

Usage Examples

Default Options

grunt.initConfig({
  csspreload: {
    options: {},
    files: {
      'build/output.css': ['build/output.css'],
    },
  },
});

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.

Release History

1.0.0 Initial release

Usage no npm install needed!