function-composer

function-composer

Compose functions with multiple type signatures.

Supported environments: node.js, Chrome, Firefox, Safari, Opera, IE9+.

Load

Install via npm:

npm install function-composer

Usage

Example usage:

var compose = require('function-composer');

// compose a new function
var fn = compose({
  'number': function (a) {
    return 'a is a number';
  },
  'number, boolean': function (a, b) {
    return 'a is a number, b is a boolean';
  },
  'number, number': function (a, b) {
    return 'a is a number, b is a number';
  }
});

// use the function
console.log(fn(2, true));      // outputs 'a is a number, b is a boolean'
console.log(fn(2));            // outputs 'a is a number'

// calling the function with a non-supported type signature will throw an error
try {
  fn('hello world');
}
catch (err) {
  console.log(err.toString()); // outputs: 'TypeError: Wrong function signature'
}

Roadmap

• Create named functions.
• Add new types (already possible but not yet documented)
• Automatic casting, for example from boolean to number.
• Extend function signatures:
  • Any type arguments like *, boolean.
  • Ellipsis like string, ....
  • Optional arguments like number?, array.
• Create a good benchmark, to get insight in the overhead.
• Add a bundle for use in the browser.

Changelog

2014-10-21, version 0.1.0

• Implemented support for functions with zero, one, or multiple arguments.