stdio

Module for input/output management with nodejs.

1. Installation

To install the most recent release from npm, run:

npm install stdio

2. Usage

You can do many things with this module

2.1. Parse Unix-like command line options

var stdio = require('stdio');
var ops = stdio.getopt({
    'check': {key: 'c', args: 2, description: 'What this option means'},
    'map': {key: 'm', description: 'Another description', mandatory: true},
    'kaka': {key: 'k', args: 2, mandatory: true},
    'ooo': {key: 'o'}
});
console.log(ops);

If you run the previous example with the command

node pruebas.js -c 23 45 88 --map -k 23 44 cosa

Program output will be:

{ check: [ '23', '45' ],
  args: [ '88', 'cosa' ],
  map: true,
  kaka: [ '23', '44' ] }

So you can check options:

if(ops.map){
    // Your action
}
if(ops.kaka){
    // Your action, using ops.kaka[0] or ops.kaka[1] or...
}

As you can see, every option in ops object can has 3 different type of values:

• The boolean value true if it has been specified without an args attribute.
• A single string if it has been specified with args: 1.
• A string array, if it has been specified with args >= 2.

Print usage

This module can generate an usage message automatically. You can use it when user specifies --help option, which is automatically supported. This code:

var stdio = require('stdio');

var ops = stdio.getopt({
	una: {description: 'Sets something to some value', key: 'u', args: 2, mandatory: true},
	otra_muy_larga: {description: 'A boolean flag', key: 'o', mandatory: true},
	una_sin_desc: {description: 'Another boolean flag'},
	ultima: {description: 'A description', key: 'u', args: 1}
}, '[FILE1] [FILE2] ...'); // Optional extra arguments description

will produce the following output (if it is called with --help flag):

USAGE: node something.js [OPTIONS] [FILE1] [FILE2] ...
  -u, --una <ARG1> <ARG2> 	Sets something to some value (mandatory)
  -o, --otra_muy_larga    	A boolean flag (mandatory)
  --una_sin_desc          	Another boolean flag
  -u, --ultima <ARG1>     	A description

If a non-spected option is given or a mandatory option is not, an error (followed by the usage message) will be shown, finishing your program automatically. It's cool, isn`t it?

2.2. Read standard input at once

var stdio = require('stdio');
stdio.read(function(data){
    console.log(data);
});

2.3. Printf-like output

This simple line:

stdio.printf('example %d: %s is %j\n', 2, 'any', {a: 2, b: [0, 2, 8], c: 'str'});

will produce the following output:

example 2: any is {"a":2,"b":[0,2,8],"c":"str"}

You can use %s for strings, %d for numbers (integer or floating-point ones), and %j for JSON objects.

3. Testing

To run tests, use the following command from module's root:

npm test

Changelog

0.1.1

• Grouped short options support added (for boolean flags). Now you can write -abc instead of -a -b -c.
• Usage message has been simplified. Extra arguments description is supported now.

0.1.0

• If an option is specified with less arguments than the specified, an error (and the help message) is shown and program finishes.
• Captured options now has 3 possible values: true, a single string or an array of strings. Much easier to use than in previous releases (but incompatible with them, so be careful updating).

Projects using stdio module

The following projects are currently using stdio module:

• mammock: https://github.com/earmbrust/mammock

If you use this module in your project, please, let us know.