Superoverload

Superoverload is a function overload for JavaScript.

Usage

Superoverload expects functions and their signatures as arguments. Like this:

const overload = require('superoverload');

const fn = overload(
  ['number'],
  a => 'It is a number',

  ['string'],
  a => 'It is a string',
);

fn(1); // => 'It is a number'
fn(''); // => 'It is a string'

You can pass odd number of arguments, then the fisrt will be interpreted as default function. Default means, that it will be called if all over functions do not have corresponding signature.

const overload = require('superoverload');

const fn = overload(
  a => 'It is something else',

  ['number'],
  a => 'It is a number',
);

fn(1); // => 'It is a number'
fn(''); // => 'It is something else'

Optional parameters

Superoverload can be used to declare optional parameters.

function getFullUrl(protocol, host, port, path) {
    return protocol + '://' + host + (port ? ':' + port : '') + path;
}

const getUrl = overload(
    ['string'],
    path => getFullUrl('http', 'example.com', '', path),

    ['string', 'string'],
    (host, path) => getFullUrl('http', host, '', path),

    ['string', 'number', 'string']
    (host, port, path) => getFullUrl('http', host, String(port), path)
);

getUrl('/some/path'); // => 'http://example.com/path'
getUrl('my.example.com', 8080, '/some/path'); // => 'http://my.example.com:8080/somepath'