Less + newer: Watch for imported file changes

gistfile1.js

//
// grunt-newer: 
// Check for newer @import .less files example
// See: https://github.com/tschaub/grunt-newer/issues/29
//
grunt.initConfig({
// ...
    newer: {
        options: {
            override: function(details, include) {
                if (details.task === 'less') {
                    checkForNewerImports(details.path, details.time, include);
                }
                else {
                    include(false);
                }
            }
        }
    }
// ...
});

var fs = require('fs');
var path = require('path');

function checkForNewerImports(lessFile, mTime, include) {
    fs.readFile(lessFile, "utf8", function(err, data) {
        var lessDir = path.dirname(lessFile),
            regex = /@import "(.+?)(\.less)?";/g,
            shouldInclude = false,                
            match;

        while ((match = regex.exec(data)) !== null) {
            // All of my less files are in the same directory,
            // other paths may need to be traversed for different setups...
            var importFile = lessDir + '/' + match[1] + '.less';
            if (fs.existsSync(importFile)) {
                var stat = fs.statSync(importFile);
                if (stat.mtime > mTime) {
                    shouldInclude = true;
                    break;
                }
            }
        }
        include(shouldInclude);
    });
}