How can I dynamically generate a list of filenames for use in a task with Grunt?

gruntjs, javascript, node.js

Solution

Basic Principle

Here's a way to do it that uses Grunt's file matching capabilities to get a list of files. The following code will seek templates in a subdirectory named `templates`. You just need to put your `php` files there and the script will find it. Note I've omitted the use of `load-grunt-config` since it is not a factor in the specific problem of getting a list of files.

The key is to use `grunt.file.expand` to get the files.

module.exports = function (grunt) {

    // List all files in the templates directory.
    var templates = grunt.file.expand({filter: "isFile", cwd: "templates"},
                                      ["*"]);

    // Make actual choices out of them that grunt-prompt can use.
    var choices = templates.map(function (t) {
        return { name: t, checked: false};
    });

    grunt.initConfig({
        prompt: {
            init: {
                options: {
                    questions: [{
                        // Set the authors name
                        config: 'init.author.name',
                        type: 'input',
                        message: 'What is your name?'
                    }, {
                        // Set the name of the project
                        config: 'init.project.name',
                        type: 'input',
                        message: 'What is the name of your project?'
                    }, {
                        // Select templates to be used
                        config: 'init.php.templates',
                        type: 'checkbox',
                        message: 'Which templates do you want to use?',
                        choices: choices
                    }]
                }
            }
        }
    });

    grunt.task.loadNpmTasks("grunt-prompt");
    grunt.registerTask("default", ["prompt"]);
};

You could use something more sophisticated than `"*"` as a pattern. For instance, if you are going to have other types of files there that you don't want to list `"*.php"` would be indicated. I also use `isFile` for the `filter` option to avoid listing directories. And I use `cwd` to change the working directory to `templates` before listing the files, which means the file names returned do not include `templates/` in their name. It would also be possible to do this instead:

var templates = grunt.file.expand({filter: "isFile"}, ["templates/*"]);

and get a list of files that include the `templates/` directory in their name.

With `load-grunt-config`

By default, `load-grunt-config` wants a `package.json` file (because it calls `load-grunt-tasks`). This is what I've used:

{
  "dependencies": {
    "load-grunt-config": "^0.8.0",
    "grunt-prompt": "^1.1.0",
    "grunt": "^0.4.4"
  }
}

The `Gruntfile.js` becomes:

module.exports = function (grunt) {

    grunt.registerTask("default", ["prompt"]);
    require('load-grunt-config')(grunt);
};

And then in `grunt/prompt.js` you need this:

module.exports = function(grunt) {
    // List all files in the templates directory.
    var templates = grunt.file.expand({filter: "isFile", cwd: "templates"},
                                      ["*"]);

    // Make actual choices out of them that grunt-prompt can use.
    var choices = templates.map(function (t) {
        return { name: t, checked: false};
    });

    return {
        init: {
            options: {
                questions: [{
                    // Set the authors name
                    config: 'init.author.name',
                    type: 'input',
                    message: 'What is your name?'
                }, {
                    // Set the name of the project
                    config: 'init.project.name',
                    type: 'input',
                    message: 'What is the name of your project?'
                }, {
                    // Select templates to be used
                    config: 'init.php.templates',
                    type: 'checkbox',
                    message: 'Which templates do you want to use?',
                    choices: choices
                }]
            }
        }
    };
};

Problem

Original source