grunt-templater にパス取得用のヘルパー。現在処理中のテンプレートのパスやファイル名の取得などが行える…はず。$ npm install grunt grunt-templater ejs

Gruntfile.js

module.exports = function(grunt)
{
    'use strict';

    var ROOT_PATH = '.',
        TEMPLATE_PATH = ROOT_PATH + '/templates';

    grunt.config.init({
        template: {
            hoge: {
                src:  TEMPLATE_PATH + '/sample.ejs',
                dest: ROOT_PATH + '/sample.html',
                variables: {},
            },
            fuga: {
                src:  TEMPLATE_PATH + '/sample.ejs',
                dest: ROOT_PATH + '/htdocs/sample.html',
                variables: {},
            },
            foo: {
                src:  TEMPLATE_PATH + '/sample.ejs',
                dest: ROOT_PATH + '/htdocs/dir/sample.html',
                variables: {},
            },
            news: {
                src:  TEMPLATE_PATH + '/sample.ejs',
                dest: ROOT_PATH + '/news/sample.html',
                variables: {},
            },
        },
    });

    grunt.task.loadNpmTasks('grunt-templater');
    grunt.task.renameTask('template', 'grunt-templater_template');

    grunt.task.registerMultiTask('template',
        'generates an html file from a specified template',
        (function() {
            var p = require('path'),
                rootPath    = null,
                currentPath = null,
                Path = {
                    getRelative: function(to, from)
                    {
                        var path, dirTo, dirFrom, basename, re;

                        to   = this.normalize(to);
                        from = this.normalize(from) || currentPath;

                        dirTo    = trimRootPath(p.dirname(to  )) || '.';
                        dirFrom  = trimRootPath(p.dirname(from)) || '.';
                        path     = p.relative(dirFrom, dirTo);
                        basename = trimRootPath(p.basename(to));
                        path     = path + (path ? p.sep : '') + basename;

                        return p.normalize(path);
                    },

                    getAbsolute: function(to, from)
                    {
                        return this.toAbsolute(this.getRelative(to, from));
                    },

                    toAbsolute: function(path)
                    {
                        return p.normalize(p.sep + path);
                    },

                    getRoot: function()
                    {
                        return this.getRelative(rootPath, currentPath);
                    },

                    getCurrent: function()
                    {
                        return trimRootPath(currentPath);
                    },

                    setCurrent: function(path)
                    {
                        currentPath = p.normalize(path);
                        rootPath    = getRootPath(path);
                        return this;
                    },

                    getDirname: function(path)
                    {
                        return p.dirname(path);
                    },

                    getBasename: function(path)
                    {
                        return p.basename(path);
                    },
                    
                    normalize: function(path)
                    {
                        if (path && path.indexOf(p.sep) === 0) {
                            path = p.normalize(rootPath + path);
                        }
                        
                        return path;
                    },
                };

            function trimRootPath(path)
            {
                var re = new RegExp('^' + quote(rootPath + p.sep) + '?');
                return path.replace(re, '');
            }

            function getRootPath(path)
            {
                var root = path.split(p.sep).slice(0, 2).join(p.sep);
                return p.dirname(root);
            }

            function quote(str)
            {
                return (str + '').replace(/([.?*+^$[\]\\(){}|-])/g, "\\$1");
            }

            return function() {
                var config = {};
                this.data.variables.Path = Path.setCurrent(this.data.dest);
                config[this.target] = this.data;
                grunt.config.set('grunt-templater_template', config);
                grunt.task.run(['grunt-templater_template']);
            };
        }())
    );
};

sample.ejs

Path.getCurrent() -> <%= Path.getCurrent() %>
Path.getRoot() -> <%= Path.getRoot() %>
Path.toAbsolute(Path.getCurrent()) -> <%= Path.toAbsolute(Path.getCurrent()) %>
Path.toAbsolute(Path.getRoot()) -> <%= Path.toAbsolute(Path.getRoot()) %>
Path.getRelative() -> <%= Path.getRelative('/img/hoge.jpg') %>
Path.getAbsolute() -> <%= Path.getAbsolute('/img/hoge.jpg') %>
Path.getRelative() -> <%= Path.getRelative('fuga/hoge.html') %>