scaffolder

Helpers for making apps that scaffold stuff

Scaffolder

Scaffolder is a node package that is designed to make the process of making node CLI applications simpler. The project is a work in progress, and pull requests are definitely welcome.

I've written quite a few cli tools using node now, and initially I used commander a bit and then experimented with my own cli focused library. Once I came across nopt though everything changed, and I've been pretty much using it exclusively since.

While nopt provides amazing option parsing functionality, there are things I do find myself doing again and again when writing cli apps.

Things such as:

  • copying particular files from one place to another
  • running blocks of code in response to the user requesting a particular action from the command line

Scaffolder is designed to ease the process of making CLI apps using node by adopting some conventions for writing your CLI app.

The first thing you should probably do if you are writing a CLI application in node, is to create a simple shell script that will run your application. For my applications that make use of scaffolder such a script looks something like this:

#!/usr/bin/env node
require('scaffolder')();

This code is significantly less than what you would see in most shell scripts that kick off a node process and this is because of the conventions that Scaffolder uses.

Before reading this section, I would encourage you to read the README for the nopt package as some understanding of how nopt works will be helpful.

A CLI application built using scaffolder will likely be powered by a number of command handlers. A command handler is simply a node module (usually located in the ./commands folder for the project) that provides a number of exports that make the command work. In the simplest case a command handler will look like this:

exports.description = 'A test action';
exports.run = function(optscallback) {
    callback(null, 'ok');
};

Typically, though a command handler will use a variety of command-line flags to modify it's behaviour and these can be configured by providing an args export, e.g.

exports.args = {
    url:    'url',
    path:   path
};

These arguments are defined as per standard nopt options and an optional shorthand export can also be provided to provide shorthand equivalents for the defined options.

Once defined in the args export, any arguments that are parsed successfully from process.argv will be provided as part of the opts object that is passed into the run function declared in the command handler.

When scaffolder is run (using require('scaffolder')()) a number of default options are passed through, but these can be overriden by providing an options object. The defaults of this options object are shown below:

require('scaffolder')({
  // an array of default command strings that will attempt to 
  // be invoked if no options are provided 
  defaultCommands: [],  
 
  // provide any default args that individual commands  
  // will incorporate / overwrite 
  defaultArgs: {},
 
  // default nopt shorthand options  
  defaultShorthand: {},
 
  // the path the scaffolder commands will be loaded from 
  commandPath: '', // defaults to the commands/ folder of the project 
});

When running an action, scaffolder provides a number of helper methods for performing common tasks.

scaffolder.copy(src, dst, callback);

The copy method provides an interface to the really useful ncp which can be used to copy all the files in src to dst. The scaffolder copy method also ensures that the dst directory exists before starting the copy operation.

NOTE: The src path is relative to the npm package that has incorporated scaffolder (unless absolute), but dst path is relative to the cwd.

Get the path the scaffolder considers the source path

Request either a single prompt from the user, or a series of prompts and then return the results from the prompt.

Run the requested command with the supplied opts (if provided). Upon completion of the command the callback will be triggered.

deprecated

Copyright (c) 2014 Damon Oehlman damon.oehlman@gmail.com

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