exec-promise
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Testable CLIs with promises
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# exec-promise
[](http://travis-ci.org/JsCommunity/exec-promise)
[](https://david-dm.org/JsCommunity/exec-promise)
[](https://david-dm.org/JsCommunity/exec-promise#info=devDependencies)
> Testable CLIs with promises
**Features**
- executes the passed function with command line arguments
- wait for completion (sync or promise) before stopping Node
- in case of exception: pretty print the value and exit with exit code 1
- in case of returned value (not undefined):
- if valid exit code (integer), exit Node with it
- otherwise, pretty print it
## Introduction
**TODO**
- executables should be testable
- the execution flow should be predictable and followable (promises)
## Install
Download [manually](https://github.com/JsCommunity/exec-promise/releases) or with package-manager.
#### [npm](https://npmjs.org/package/exec-promise)
```
npm install --save exec-promise
```
This library requires promises support, for Node versions prior to 0.12 [see
this page](https://github.com/JsCommunity/js-promise-toolbox#usage) to
enable them.
## Example
### ES 2015
```javascript
import execPromise from 'exec-promise'
// - The command line arguments are passed as first parameter.
// - Node will exists as soon as the promise is settled (with a code
// different than 0 in case of an error).
// - All errors are catched and properly displayed with a stack
// trace.
// - Any returned value (i.e. not undefined) will be prettily
// displayed
execPromise(async args => {
// ... do what you want here!
})
```
### ES5
```javascript
module.exports = function (args) {
if (args.indexOf('-h') !== -1) {
return 'Usage: my-program [-h | -v]'
}
if (args.indexOf('-v') !== -1) {
var pkg = require('./package')
return 'MyProgram version ' + pkg.version
}
var server = require('http').createServer()
server.listen(80)
// The program will run until the server closes or encounters an
// error.
return require('event-to-promise')(server, 'close')
}
// Executes the exported function if this module has been called
// directly.
if (!module.parent) {
require('exec-promise')(module.exports)
}
```
## Contributing
Contributions are *very* welcome, either on the documentation or on
the code.
You may:
- report any [issue](https://github.com/JsCommunity/human-format/issues)
you've encountered;
- fork and create a pull request.
## License
ISC © [Julien Fontanet](http://julien.isonoe.net)