yargs-common-bin

Abstraction bin tool wrap yargs, to provide more convenient usage, support async / generator.

Install

$ npm i yargs-common-bin --save

Build a bin tool for your team

You maybe need a custom xxx-bin to implement more custom features.

Now you can implement a Command sub class to do that.

Example: Write your own git command

This example will show you how to create a new my-git tool.

• Full demo: my-git

test/fixtures/my-git
├── bin
│   └── my-git.js
├── command
│   ├── remote
│   │   ├── add.js
│   │   └── remove.js
│   ├── clone.js
│   └── remote.js
├── index.js
└── package.json

my-git.js

#!/usr/bin/env node

'use strict';

const Command = require('..');
new Command().start();

Main Command

Just extend Command, and use as your bin start point.

You can use this.yargs to custom yargs config, see http://yargs.js.org/docs for more detail.

const Command = require('yargs-common-bin');
const pkg = require('./package.json');

class MainCommand extends Command {
  constructor(rawArgv) {
    super(rawArgv);
    this.usage = 'Usage: my-git <command> [options]';

    // load entire command directory
    this.load(path.join(__dirname, 'command'));

    // or load special command file
    // this.add(path.join(__dirname, 'test_command.js'));

    // more custom with `yargs` api, such as you can use `my-git -V`
    this.yargs.alias('V', 'version');
  }
}

module.exports = MainCommand;

CloneCommand

const Command = require('yargs-common-bin');
class CloneCommand extends Command {
  constructor(rawArgv) {
    super(rawArgv);

    this.options = {
      depth: {
        type: 'number',
        description: 'Create a shallow clone with a history truncated to the specified number of commits',
      },
    });
  }

  * run({ argv }) {
    console.log('git clone %s to %s with depth %d', argv._[0], argv._[1], argv.depth);
  }

  get description() {
    return 'Clone a repository into a new directory';
  }

  get aliases() {
    return ['command-aliases', 'ca']
  }
}

module.exports = CloneCommand;

Run result

$ my-git clone gh://node-modules/common-bin dist --depth=1

git clone gh://node-modules/common-bin to dist with depth 1

Concept

Command

Define the main logic of command

Method:

• start() - start your program, only use once in your bin file.
• run(context)
  • should implement this to provide command handler, will exec when not found sub command.
  • Support generator / async function / normal function which return promise.
  • context is { cwd, env, argv, rawArgv }
    • cwd - process.cwd()
    • env - clone env object from process.env
    • argv - argv parse result by yargs, { _: [ 'start' ], '$0': '/usr/local/bin/common-bin', baseDir: 'simple'}
    • rawArgv - the raw argv, [ "--baseDir=simple" ]
• load(fullPath) - register the entire directory to commands
• add(name, target) - register special command with command name, target could be full path of file or Class.
• showHelp() - print usage message to console.
• options= - a setter, shortcut for yargs.options
• usage= - a setter, shortcut for yargs.usage

Properties:

• description - {String} a getter, only show this description when it's a sub command in help console
• helper - {Object} helper instance
• yargs - {Object} yargs instance for advanced custom usage
• options - {Object} a setter, set yargs' options
• version - {String} customize version, can be defined as a getter to support lazy load.
• aliases - {Array} current command aliases
• parserOptions - {Object} control context parse rule.
  • execArgv - {Boolean} whether extract execArgv to context.execArgv
  • removeAlias - {Boolean} whether remove alias key from argv
  • removeCamelCase - {Boolean} whether remove camel case key from argv

You can define options by set this.options

this.options = {
  baseDir: {
    alias: 'b',
    demandOption: true,
    description: 'the target directory',
    coerce: str => path.resolve(prcess.cwd(), str),
  },
  depth: {
    description: 'level to clone',
    type: 'number',
    default: 1,
  },
  size: {
    description: 'choose a size',
    choices: ['xs', 's', 'm', 'l', 'xl'],
  },
};

You can define version by define this.version getter:

get version() {
  return 'v1.0.0';
}

Helper

• forkNode(modulePath, args, opt) - fork child process, wrap with promise and gracefull exit
• spawn(cmd, args, opt) - spawn a new process, wrap with promise and gracefull exit
• npmInstall(npmCli, name, cwd) - install node modules, wrap with promise
• * callFn(fn, args, thisArg) - call fn, support gernerator / async / normal function return promise
• unparseArgv(argv, opts) - unparse argv and change it to array style

Extend Helper

// index.js
const Command = require('yargs-common-bin');
const helper = require('./helper');
class MainCommand extends Command {
  constructor(rawArgv) {
    super(rawArgv);

    // load sub command
    this.load(path.join(__dirname, 'command'));

    // custom helper
    Object.assign(this.helper, helper);
  }
}

Advanced Usage

Single Command

Just need to provide options and run().

const Command = require('yargs-common-bin');
class MainCommand extends Command {
  constructor(rawArgv) {
    super(rawArgv);
    this.options = {
      baseDir: {
        description: 'target directory',
      },
    };
  }

  *run(context) {
    console.log('run default command at %s', context.argv.baseDir);
  }
}

Sub Command

Also support sub command such as my-git remote add <name> <url> --tags.

// test/fixtures/my-git/command/remote.js
class RemoteCommand extends Command {
  constructor(rawArgv) {
    // DO NOT forgot to pass params to super
    super(rawArgv);
    // load sub command for directory
    this.load(path.join(__dirname, 'remote'));
  }

  *run({ argv }) {
    console.log('run remote command with %j', argv._);
  }

  get description() {
    return 'Manage set of tracked repositories';
  }
}

// test/fixtures/my-git/command/remote/add.js
class AddCommand extends Command {
  constructor(rawArgv) {
    super(rawArgv);

    this.options = {
      tags: {
        type: 'boolean',
        default: false,
        description: 'imports every tag from the remote repository',
      },
    };
  }

  *run({ argv }) {
    console.log(
      'git remote add %s to %s with tags=%s',
      argv.name,
      argv.url,
      argv.tags,
    );
  }

  get description() {
    return 'Adds a remote named <name> for the repository at <url>';
  }
}

see remote.js for more detail.

Async Support

class SleepCommand extends Command {
  async run() {
    await sleep('1s');
    console.log('sleep 1s');
  }

  get description() {
    return 'sleep showcase';
  }
}

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

see async-bin for more detail.