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stampit

stampit

Stampit Build Status npm Gitter Twitter Follow CDNJS UNPKG

Create objects from reusable, composable behaviors

Stampit is a 1.3KB gzipped (or 2.7K minified) JavaScript module which supports three different kinds of prototypal inheritance (delegation, concatenation, and functional) to let you inherit behavior in a way that is much more powerful and flexible than any other Object Oriented Programming model.

Stamps are standardised composable factory functions. Stampit is an infected compose featuring friendly handy API.

Find many more examples in this series of mini blog posts.

Example

import stampit from 'stampit'
 
const Character = stampit({
  props: {
    name: null,
    health: 100
  },
  init({ name = this.name }) {
    this.name = name
  }
})
 
const Fighter = stampit(Character, { // inheriting
  props: {
    stamina: 100
  },
  init({ stamina = this.stamina }) {
    this.stamina = stamina;    
  },
  methods: {
    fight() {
      console.log(`${this.name} takes a mighty swing!`)
      this.stamina--
    }
  }
})
 
const Mage = stampit(Character, { // inheriting
  props: {
    mana: 100
  },
  init({ mana = this.mana }) {
    this.mana = mana;    
  },
  methods: {
    cast() {
      console.log(`${this.name} casts a fireball!`)
      this.mana--
    }
  }
})
 
const Paladin = stampit(Mage, Fighter) // as simple as that!
 
const fighter = Fighter({ name: 'Thumper' })
fighter.fight()
const mage = Mage({ name: 'Zapper' })
mage.cast()
const paladin = Paladin({ name: 'Roland', stamina: 50, mana: 50 })
paladin.fight()
paladin.cast()
 
console.log(Paladin.compose.properties) // { name: null, health: 100, stamina: 100, mana: 100 }
console.log(Paladin.compose.methods) // { fight: [Function: fight], cast: [Function: cast] }

Status

Install

Via NPM: NPM

Via bower:

$ bower install stampit
or
$ bower install stampit=https://npmcdn.com/stampit@4/dist/stampit.min.js
or
$ bower install stampit=https://unpkg.com/stampit@4.0.1/src/stampit.js

Browsers: CDNJS UNPKG

Compatibility

Stampit should run fine in any ES5 browser or any node.js.

API

See the API.

What's the Point?

Prototypal OO is great, and JavaScript's capabilities give us some really powerful tools to explore it, but it could be easier to use.

Basic questions like "how do I inherit privileged methods and private data?" and "what are some good alternatives to inheritance hierarchies?" are stumpers for many JavaScript users.

Let's answer both of these questions at the same time.

// Some privileged methods with some private data.
const Availability = stampit().init(function() {
  var isOpen = false; // private
 
  this.open = function open() {
    isOpen = true;
    return this;
  };
  this.close = function close() {
    isOpen = false;
    return this;
  };
  this.isOpen = function isOpenMethod() {
    return isOpen;
  }
});
 
// Here's a stamp with public methods, and some state:
const Membership = stampit({
  props: {
    members: {}
  },
  methods: {
    add(member) {
      this.members[member.name] = member;
      return this;
    },
    getMember(name) {
      return this.members[name];
    }
  }
});
 
// Let's set some defaults:
const Defaults = stampit({
  props: {
    name: 'The Saloon',
    specials: 'Whisky, Gin, Tequila'
  },
  init({name, specials}) {
    this.name = name || this.name;
    this.specials = specials || this.specials;
  }
});
 
// Classical inheritance has nothing on this.
// No parent/child coupling. No deep inheritance hierarchies.
// Just good, clean code reusability.
const Bar = stampit(Defaults, Availability, Membership);
 
// Create an object instance
const myBar = Bar({name: 'Moe\'s'});
 
// Silly, but proves that everything is as it should be.
myBar.add({name: 'Homer'}).open().getMember('Homer');

For more examples see the API.

React Users. Stampit loves React. Check out react-stamp for composable components.

Development

Unit tests

npm t

Unit and benchmark tests

env CI=1 npm t

Unit tests in a browser

To run unit tests in a default browser:

npm run browsertest

To run tests in a different browser:

  • Open the ./test/index.html in your browser, and
  • open developer's console. The logs should indicate success.