grunt-less-imports/tasks/less_imports.js

A grunt task to create LessCSS @import statements from a collection of stylesheet files

/*
 * grunt-less-imports
 * https://github.com/MarcDiethelm/grunt-less-imports
 *
 * Copyright (c) 2013-2016 Marc Diethelm
 * Licensed under the MIT license.
 */

'use strict';

var path = require('path');
var util = require('util');
var slash = require('slash');
var errorImportCallback;

module.exports = function(grunt) {
	// Please see the Grunt documentation for more information regarding task
	// creation: http://gruntjs.com/creating-tasks

	grunt.registerMultiTask('less_imports', 'A grunt task to create @import statements from a collection of stylesheet files.', function() {

		// Merge task-specific and/or target-specific options with these defaults.
		var options = this.options({
			inlineCSS: true,
			banner: '// This file was generated by grunt-less-imports',
			import: 'once'
		});
		var banner = options.banner + '\n\n';

		// Iterate over all specified file groups.
		this.files.forEach(function(f) {

			var css = '';
			var lessImports = '';
			var dest = f.dest;
			var relRoot = path.dirname(dest);
			var resolved;
			var slashed;
			var i = 0;
			var filepath;
			var extension;
			var importStr;

			if ('function' !== typeof options.import) {
				importStr = options.import;
			}

			// Process sources "f.src.forEach";

			for (; i < f.src.length; i++) {
				filepath = f.src[i];

				// Warn on and ignore invalid source files (e.g. if nonull was set).
				if (!grunt.file.exists(filepath)) {
					grunt.log.warn('Source file "' + filepath + '" not found.');
				} else {
					extension = filepath.split('.').pop();
					if (options.inlineCSS === true && extension === 'css') {
						grunt.log.debug(filepath.green+ ' appending css'.magenta);
						css += grunt.file.read(filepath) + '\n\n';
					}
					else {
						resolved = path.relative(relRoot, filepath);
						slashed = slash(resolved);
						grunt.log.debug(slashed.green + ' @import created'.magenta);

						if ('function' === typeof options.import) {
							importStr = options.import(filepath, extension);
							if ('string' !== typeof importStr) {
								errorImportCallback(filepath, extension);
							}
						}
						lessImports += util.format('@import (%s) "%s";\n', importStr, slashed);
					}
				}
			}

			// Write the destination file.
			grunt.file.write(dest, banner + css + lessImports);
			grunt.log.writeln('File "' + f.dest.cyan + '" created.');
		});
	});

	errorImportCallback = function errorImportCallback(filepath, extension, importFunc) {
		var error = grunt.util.error(util.format(
			'options.import callback given, but no string returned.\n' +
			'Arguments passed: ["%s", "%s"].', filepath, extension)
		);
		grunt.fail.warn(error);
	};

};