@iarna/cli

Some simple CLI scaffolding for promise returning applications.


EXAMPLE

example.js
``js
require('@iarna/cli')(main)

const util = require('util');
const sleep = util.promisify(setTimeout);

// opts will only contain the _ var, for compatibility with yargs
async function main (opts, arg1, arg2, arg3) {
console.log('Got:', arg1, arg2, arg3)
await sleep(40)
}
`

WHAT YOU GET

Automatic glob parsing on Windows so that your passing .foo works the
same on Mac/Linux/Windows.
* Error detetion and handling:
* _exit without resolving warnings_ - If your program finishes without
resolving its promises (like if it crashes hard or you process.exit, or
you just don't resolve the promise) then we warn about that.
* If your entry point function rejects then that's reported with a stack
trace (if the rejected value has .stack) else with the rejected value
and your process will exit with an error code.
* Optional yargs support. If yargs is requirable then it will be used.
The wrapper around the main function returns a yargs object, so you can
configure it as usual. The argv object is passed in as the first
argument of your entry point function. The rest of your positional
arguments are passed in as the remaining function arguments.
* Optional update-notifier support. If update-notifier is requirable
then it will be used. A default update notifier is setup for your app so
users will learn about new versions when you publish them. Your app needs
to have a name, version and bin entry in its package.json. (The bin
entry needs to have the script using @iarna/cli in it for the update
notifier to trigger.)

With Yargs

If you have yargs installed as a dependency you can customize it further by
chaining off the require in the usual yargsish way.

example.js
`js
require('@iarna/cli')(main)
.boolean('silent')
.boolean('exit')
.boolean('error')
.boolean('reject')
.boolean('code50')
.version()
.help()

const util = require('util');
const sleep = util.promisify(setTimeout);

function main (opts, arg1, arg2, arg3) {
if (!opts.silent) console.error('Starting up!')
console.log('Got:', arg1, arg2, arg3)
if (opts.exit) process.exit()
if (opts.error) throw new Error('throw')
if (opts.reject) return Promise.reject(new Error('reject'))
if (opts.code50) return Promise.reject(50)
return sleep(10000)
}

// alternatively use:
// function main (opts, ...args) {
`

`console
$ node example hello there world
Starting up!
Got: hello there world
$ node example hello there world
Starting up!
Got: hello there world
^C
Abnormal exit: SIGINT
$ node example --silent hello there world
Got: hello there world
$ node example --silent hello there world --exit
Got: hello there world
Abnormal exit: Promises not resolved
$ node example --silent hello there world --error
Got: hello there world
Error: throw
at main (/Users/rebecca/code/cli/example.js:11:25)
at Immediate.setImmediate (/Users/rebecca/code/cli/app.js:38:32)
at runCallback (timers.js:800:20)
at tryOnImmediate (timers.js:762:5)
at processImmediate [as _immediateCallback] (timers.js:733:5)
$ node example --silent hello there world --reject
Got: hello there world
Error: reject
at main (/Users/rebecca/code/cli/example.js:12:42)
at Immediate.setImmediate [as _onImmediate] (/Users/rebecca/code/cli/app.js:38:32)
at runCallback (timers.js:800:20)
at tryOnImmediate (timers.js:762:5)
at processImmediate [as _immediateCallback] (timers.js:733:5)
$ node example --silent hello there world --code50
Got: hello there world
$ echo $?
50
`

WHAT ITS NOT

A full framework for writing cli apps. You'll likely outgrow the error
handling pretty fast if this is anything beyond a little one off. This
mostly exists to scratch my own itch. I kept on writing this code and I
wanted to stop. =D

It's designed to be only be as heavy as it needs to be. It only has one
direct dependency, but it can provide enhanced functionality if you depend on
yargs or update-notifier.

USAGE

$3

The module itself exports a function that you need to call with the name of
your main function. Your main function is like main in C, it's the entry
point for your program. It needs to return a promise that resolves when
your program completes.

The return value from the call is, if you have yargs installed, a yargs
object you can use to configure what options your script takes. If you
don't have yargs installed then it's a proxy that throws if you try to do
anything with it.

Your entry point function can be named anything, but it needs to return a
promise and it takes arguments like this:

main(opts, arg1, arg2, …, argn) → Promise

If you have yargs installed then the opts argument is yargs.argv
and the additional arguments are from argv._, so arg1 === argv._[0],
arg2 === argv._[1] and so on.

If you don't have yargs installed then opts argument is an object with
an _ property containing all arguments, for compatibility with the yargs
mode. As with that mode arg1 === argv._[0], arg2 === argv._[1]` and so
on.