main

node-main

A very basic module that only runs code if the script is ran directly (e.g. calling node script). It will not call the code if the script has been required (e.g. require('script')).

node-main utilizes optimist for argument parsing.

Installation & Usage

npm install main

require('main')

Once required, you can chain the functions below

.flags(options)

options follows the optimist format for options, but groups them together, e.g.:

require('main').flags({
    f: { alias: 'flag' },
    t: { alias: 'secondFlag' },
    d: { demand: true },
    // ...
})

.run(fn)

fn is the callback that will be invoked when the script is ran directly from a terminal. It can take the following parameters:

fn(argv, exit)

• argv is the parsed optimist argv object
• exit is a helper function that can be used to exit the script. It follows the form exit(exitCode, optionalMessage). If no exit code if provided, it will exit with 0 (success).

Example

#!/usr/bin/env node

exports.isTrue = function(value) { // just to get a point across...
    return value === true;
};

require('main')
.flags({
    v: { alias: 'valid', 'boolean': true, 'default': false }
})
.run(function(argv, exit) {
    if (exports.isTrue(argv.valid)) {
        exit();
    } else {
        exit(1, 'optional error message');
    }
});

Running from the terminal ($? indicates exit status):

    > node scriptAbove.js --valid
    > $?
    0
    > node scriptAbove.js
    optional error message
    > $?
    1

Using the module from another script will not execute the code in main:

var scriptAbove = require('./scriptAbove');
console.log(scriptAbove.valid('hello')); // 'false'
console.log(scriptAbove.valid(true)); // 'true'