https://github.com/eddywashere/yargs-promise

Use the headless yargs parser with promises!
https://github.com/eddywashere/yargs-promise

Last synced: 10 days ago
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Use the headless yargs parser with promises!

• Host: GitHub
• URL: https://github.com/eddywashere/yargs-promise
• Owner: eddywashere
• License: mit
• Created: 2017-04-25T20:41:22.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2023-01-12T06:39:18.000Z (almost 2 years ago)
• Last Synced: 2024-10-14T10:23:03.019Z (24 days ago)
• Language: JavaScript
• Size: 208 KB
• Stars: 5
• Watchers: 2
• Forks: 0
• Open Issues: 14
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# yargs-promise

Use the headless yargs parser with promises!

## Install

npm

```

npm install --save yargs-promise

```

yarn

```

yarn add --save yargs-promise

```

## Usage

Instead of using a callback with  [yargs.parse](http://yargs.js.org/docs/#methods-parseargs-context-parsecallback), use a promise chain: `parser.parse(text).then().catch()`.

Examples:

```js

const yargs = require('yargs');

const YargsPromise = require('yargs-promise');

// create the customized yargs parser

const parser = new YargsPromise(yargs);

// setup command & command handler

parser

  .command('hello ', 'hello world parser' , ()=>{}, (argv) => {

    // resolve a promise or other value

    argv.resolve(doSomething);

    // reject stuff

    argv.reject(yourErrorData);

    // or do nothing and reject/resolve will be handled internally

    console.log('testing argv');

  })

  .help();

// parse text input and use the returned promise

parser.parse('hello world')

  .then(({data, argv}) => {

    // data is what your code resolved or what an internal command resolved

  })

  .catch(({error, argv}) => {

    // `error` is what your code rejected or an internal error from yargs

  });

```

Customizing context example

```js

const yargs = require('yargs');

const YargsPromise = require('yargs-promise');

const parser = new YargsPromise(

  yargs,

  // customize context

  {

    customContextMethod: () => {},

    foo: 'bar'

  }

);

parser

  .command('hello ', 'hello world parser' , ()=>{}, (argv) => {

    // argv now contains

    argv.customContextMethod();

    console.log(argv.foo);

  })

  .help();

```

Need access to yargs object? Work with the direct `yargs` object prior to passing it into the yargs-promise constructor. For convenience, it is also available at `parser.yargs`. 

### How it works

This library does three things:

- wraps the yargs.parse in a new Promise

  - no more callbacks

- attaches that Promises `resolve` & `reject` methods on the context passed to yargs.parse

  - this enables you to call `argv.resolve` or `argv.reject` in command handler function

- handles default behavior

  - from Error validation

  - output from internal commands like `.help()`

  - unhandled output from custom handler

Checkout the source code or tests for more information.

### Why

Building chatbots requires parsing and handling text input. This wraps up the most common needs I've come across for handling errors, simple commands, and commands with handlers.