plan.js v1.0.4

Plan.js - Values composed of Strategies

Plan.js allows consumers to create values whose logic is broken up into individual and self-contained strategies. How those strategies interact with the end-value depends on the plan-type.

Install

npm install plan.js
bower install plan.js

Usage

var Plan = require('plan.js');

// => 11
new Plan.Reduce(0)
  // Bind to strategies
  .set( 'someVal', 10 )
  // Strategy 1
  .use( function( curr ){
    return ++curr;
  })
  .use( function( curr ){
    return curr + this.someVal;
  })
  .value();

Docs

Plan()

Base class for Plans. Create a new instance:

var Plan = require('Plan');
var planA = new Plan();
var planB = Plan.create();

To create your Plan, choose an inheritence method and implement your own valueOf function. See Reduce for more details.

.set( key, val )

Sets a key to val on the object that will be bound to strategies.

.use( strategy )

Adds a strategy to the plan. Strategy may be function an object:

{
  def: function(){}
}

.value()

Runs all strategies to get the value of the plan

.clone()

Clones the current instance, data and middleware intact.

Plan.Reduce( intialValue )

A reduce plan. Initial value is passed into the reduce chain.

Examples

var Plan = require('plan.js');
// Create a plan with initial value of 0
var orderTotalPlan = new Plan.Reduce(0);

// Generic order total plan
orderTotalPlan
  // Sub-total
  .use( function( curr ){
    return this.order.items.reduce( function( a, b ){
      return a + ( b.price * b.qty )
    }, curr );
  })
  // Promo Code
  .use( function( curr ){
    var promo = promos.get( this.order.promo );
    if ( !promo ) return curr;
    return curr - ( curr * promo.rate );
  })
  // Sales tax
  .use( function( curr ){
    return curr + ( curr * this.order.taxRate );
  })
  // Only integer results in pennies
  .use( Math.round )

// Create an order model
var order = Object.create({
  id: 'my-order'
, salesTax: 0.0825
, get total (){
    return orderTotalPlan.set( 'order', this ).value();
  }
, items: [
    { name: 'Stuff', price: 1000, qty: 1 }
  , { name: 'More Stuff', price: 500, qty: 2 }
  ]
, promo: 'FALLDUMBSALE10%OFF'
});

// => 1949
order.total;

License ISC