What's an operon?

An operon is a free operation that can types can adopt.

Think of them as functors, or single-function protocols.

npm i --save operon

This module exports operon, which defines new operons, and adopt, an operon that operates on constructors, mutating them to define an operation on their prototype.

Under the hood, operons use Symbols to safely extend arbitrary prototypes.

Example

const {operon, adopts} = require('operon')

const count = operon('count')

Object [adopts] (count) (_ => 1)
Array  [adopts] (count) (_ => _.length)
String [adopts] (count) (_ => _.length)

// Types can implement operons directly
class MyType {
  [count]() {
    return 100
  }
}

console.log(count(new MyType))  // 100

// Or with adopts
class AnotherType {}
AnotherType [adopts] (count) (_ => 100)

console.log(count(new AnotherType)) // 100

console.log(count('hello'))       // 5
console.log('hello'[count]())     // equivalently, 5
console.log(count({x: 10}))       // 1
console.log([1, 20, 30][count]()) // 3