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optimist
========
Optimist is a node.js library for option parsing for people who hate option
parsing. More specifically, this module is for people who like all the --bells
and -whistlz of program usage but think optstrings are a waste of time.
With optimist, option parsing doesn't have to suck (as much).
[![build status](https://secure.travis-ci.org/substack/node-optimist.png)](http://travis-ci.org/substack/node-optimist)
examples
========
With Optimist, the options are just a hash! No optstrings attached.
-------------------------------------------------------------------
xup.js:
````javascript
#!/usr/bin/env node
var argv = require('optimist').argv;
if (argv.rif - 5 * argv.xup > 7.138) {
console.log('Buy more riffiwobbles');
}
else {
console.log('Sell the xupptumblers');
}
````
***
$ ./xup.js --rif=55 --xup=9.52
Buy more riffiwobbles
$ ./xup.js --rif 12 --xup 8.1
Sell the xupptumblers
![This one's optimistic.](http://substack.net/images/optimistic.png)
But wait! There's more! You can do short options:
-------------------------------------------------
short.js:
````javascript
#!/usr/bin/env node
var argv = require('optimist').argv;
console.log('(%d,%d)', argv.x, argv.y);
````
***
$ ./short.js -x 10 -y 21
(10,21)
And booleans, both long and short (and grouped):
----------------------------------
bool.js:
````javascript
#!/usr/bin/env node
var util = require('util');
var argv = require('optimist').argv;
if (argv.s) {
util.print(argv.fr ? 'Le chat dit: ' : 'The cat says: ');
}
console.log(
(argv.fr ? 'miaou' : 'meow') + (argv.p ? '.' : '')
);
````
***
$ ./bool.js -s
The cat says: meow
$ ./bool.js -sp
The cat says: meow.
$ ./bool.js -sp --fr
Le chat dit: miaou.
And non-hypenated options too! Just use `argv._`!
-------------------------------------------------
nonopt.js:
````javascript
#!/usr/bin/env node
var argv = require('optimist').argv;
console.log('(%d,%d)', argv.x, argv.y);
console.log(argv._);
````
***
$ ./nonopt.js -x 6.82 -y 3.35 moo
(6.82,3.35)
[ 'moo' ]
$ ./nonopt.js foo -x 0.54 bar -y 1.12 baz
(0.54,1.12)
[ 'foo', 'bar', 'baz' ]
Plus, Optimist comes with .usage() and .demand()!
-------------------------------------------------
divide.js:
````javascript
#!/usr/bin/env node
var argv = require('optimist')
.usage('Usage: $0 -x [num] -y [num]')
.demand(['x','y'])
.argv;
console.log(argv.x / argv.y);
````
***
$ ./divide.js -x 55 -y 11
5
$ node ./divide.js -x 4.91 -z 2.51
Usage: node ./divide.js -x [num] -y [num]
Options:
-x [required]
-y [required]
Missing required arguments: y
EVEN MORE HOLY COW
------------------
default_singles.js:
````javascript
#!/usr/bin/env node
var argv = require('optimist')
.default('x', 10)
.default('y', 10)
.argv
;
console.log(argv.x + argv.y);
````
***
$ ./default_singles.js -x 5
15
default_hash.js:
````javascript
#!/usr/bin/env node
var argv = require('optimist')
.default({ x : 10, y : 10 })
.argv
;
console.log(argv.x + argv.y);
````
***
$ ./default_hash.js -y 7
17
And if you really want to get all descriptive about it...
---------------------------------------------------------
boolean_single.js
````javascript
#!/usr/bin/env node
var argv = require('optimist')
.boolean('v')
.argv
;
console.dir(argv);
````
***
$ ./boolean_single.js -v foo bar baz
true
[ 'bar', 'baz', 'foo' ]
boolean_double.js
````javascript
#!/usr/bin/env node
var argv = require('optimist')
.boolean(['x','y','z'])
.argv
;
console.dir([ argv.x, argv.y, argv.z ]);
console.dir(argv._);
````
***
$ ./boolean_double.js -x -z one two three
[ true, false, true ]
[ 'one', 'two', 'three' ]
Optimist is here to help...
---------------------------
You can describe parameters for help messages and set aliases. Optimist figures
out how to format a handy help string automatically.
line_count.js
````javascript
#!/usr/bin/env node
var argv = require('optimist')
.usage('Count the lines in a file.\nUsage: $0')
.demand('f')
.alias('f', 'file')
.describe('f', 'Load a file')
.argv
;
var fs = require('fs');
var s = fs.createReadStream(argv.file);
var lines = 0;
s.on('data', function (buf) {
lines += buf.toString().match(/\n/g).length;
});
s.on('end', function () {
console.log(lines);
});
````
***
$ node line_count.js
Count the lines in a file.
Usage: node ./line_count.js
Options:
-f, --file Load a file [required]
Missing required arguments: f
$ node line_count.js --file line_count.js
20
$ node line_count.js -f line_count.js
20
methods
=======
By itself,
````javascript
require('optimist').argv
`````
will use `process.argv` array to construct the `argv` object.
You can pass in the `process.argv` yourself:
````javascript
require('optimist')([ '-x', '1', '-y', '2' ]).argv
````
or use .parse() to do the same thing:
````javascript
require('optimist').parse([ '-x', '1', '-y', '2' ])
````
The rest of these methods below come in just before the terminating `.argv`.
.alias(key, alias)
------------------
Set key names as equivalent such that updates to a key will propagate to aliases
and vice-versa.
Optionally `.alias()` can take an object that maps keys to aliases.
.default(key, value)
--------------------
Set `argv[key]` to `value` if no option was specified on `process.argv`.
Optionally `.default()` can take an object that maps keys to default values.
.demand(key)
------------
If `key` is a string, show the usage information and exit if `key` wasn't
specified in `process.argv`.
If `key` is a number, demand at least as many non-option arguments, which show
up in `argv._`.
If `key` is an Array, demand each element.
.describe(key, desc)
--------------------
Describe a `key` for the generated usage information.
Optionally `.describe()` can take an object that maps keys to descriptions.
.options(key, opt)
------------------
Instead of chaining together `.alias().demand().default()`, you can specify
keys in `opt` for each of the chainable methods.
For example:
````javascript
var argv = require('optimist')
.options('f', {
alias : 'file',
default : '/etc/passwd',
})
.argv
;
````
is the same as
````javascript
var argv = require('optimist')
.alias('f', 'file')
.default('f', '/etc/passwd')
.argv
;
````
Optionally `.options()` can take an object that maps keys to `opt` parameters.
.usage(message)
---------------
Set a usage message to show which commands to use. Inside `message`, the string
`$0` will get interpolated to the current script name or node command for the
present script similar to how `$0` works in bash or perl.
.check(fn)
----------
Check that certain conditions are met in the provided arguments.
If `fn` throws or returns `false`, show the thrown error, usage information, and
exit.
.boolean(key)
-------------
Interpret `key` as a boolean. If a non-flag option follows `key` in
`process.argv`, that string won't get set as the value of `key`.
If `key` never shows up as a flag in `process.arguments`, `argv[key]` will be
`false`.
If `key` is an Array, interpret all the elements as booleans.
.string(key)
------------
Tell the parser logic not to interpret `key` as a number or boolean.
This can be useful if you need to preserve leading zeros in an input.
If `key` is an Array, interpret all the elements as strings.
.wrap(columns)
--------------
Format usage output to wrap at `columns` many columns.
.help()
-------
Return the generated usage string.
.showHelp(fn=console.error)
---------------------------
Print the usage data using `fn` for printing.
.parse(args)
------------
Parse `args` instead of `process.argv`. Returns the `argv` object.
.argv
-----
Get the arguments as a plain old object.
Arguments without a corresponding flag show up in the `argv._` array.
The script name or node command is available at `argv.$0` similarly to how `$0`
works in bash or perl.
parsing tricks
==============
stop parsing
------------
Use `--` to stop parsing flags and stuff the remainder into `argv._`.
$ node examples/reflect.js -a 1 -b 2 -- -c 3 -d 4
{ _: [ '-c', '3', '-d', '4' ],
'$0': 'node ./examples/reflect.js',
a: 1,
b: 2 }
negate fields
-------------
If you want to explicity set a field to false instead of just leaving it
undefined or to override a default you can do `--no-key`.
$ node examples/reflect.js -a --no-b
{ _: [],
'$0': 'node ./examples/reflect.js',
a: true,
b: false }
numbers
-------
Every argument that looks like a number (`!isNaN(Number(arg))`) is converted to
one. This way you can just `net.createConnection(argv.port)` and you can add
numbers out of `argv` with `+` without having that mean concatenation,
which is super frustrating.
duplicates
----------
If you specify a flag multiple times it will get turned into an array containing
all the values in order.
$ node examples/reflect.js -x 5 -x 8 -x 0
{ _: [],
'$0': 'node ./examples/reflect.js',
x: [ 5, 8, 0 ] }
dot notation
------------
When you use dots (`.`s) in argument names, an implicit object path is assumed.
This lets you organize arguments into nested objects.
$ node examples/reflect.js --foo.bar.baz=33 --foo.quux=5
{ _: [],
'$0': 'node ./examples/reflect.js',
foo: { bar: { baz: 33 }, quux: 5 } }
installation
============
With [npm](http://github.com/isaacs/npm), just do:
npm install optimist
or clone this project on github:
git clone http://github.com/substack/node-optimist.git
To run the tests with [expresso](http://github.com/visionmedia/expresso),
just do:
expresso
inspired By
===========
This module is loosely inspired by Perl's
[Getopt::Casual](http://search.cpan.org/~photo/Getopt-Casual-0.13.1/Casual.pm).
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