chaingun

chaingun

make an object's functions chainable.

var chaingun = require('chaingun');

var chain = chaingun({
  add: function(a, b) { return a + b; },
  multiply: function(a, b) { return a * b; }
});

chain(2)
  .add(3)
  .multiply(5)
  .add(5)
  .multiply(2)
  ();  // 60

install

node:

$ npm install chaingun

browser:

$ bower install chaingun

<script src="/bower_components/chaingun/chaingun.js"></script>

api

chaingun(obj[, opts])

Returns a chainable version of the given object.

When the chainable is invoked, a chain is started. A chain consists of 'curried' versions of the original object's enumerable function properties. Each function invoked in the chain will be curried with the chain's current value, and its result used as the chain's new value. The given value will be used as the starting value for the chain. When the chain is invoked directly, its value is returned:

var chained = chaingun({add: function(a, b) { return a + b; }});

chained(2)
  .add(3)
  .add(5);
  () // 10

The chain's value can be reset explicitly by invoking the chain directly with a value:

var chained = chaingun({});
var chain = chain(2);
chain();  // 2
chain(3);
chain();  // 3

If obj is a function, it will be invoked at the start of the chain. Its return value will be used as the starting value of the chain:

function thing(a, b) { return a + b; }
thing.multiply = function(a, b) { return a * b; };

var chained = chaingun(thing);

chained(2, 3)
  .multiply(4)
  ();  // 20

if 'exits' is provided as an option, the functions with the given names will return the chain's current value instead of returning the chain:

var chained = chaingun(
  {foo: function(v) { return v * 10; }},
  {exits: ['foo']});

chained(2).foo();  // 20

if 'get' is provided as an option, it will be used as a hook whenever the chain's value is requested:

var chained = chaingun({}, {get: function(v) { return v * 10; }})
var chain = chained(2);
chain();  // 20

if 'set' is provided as an option, it will be used as a hook whenever the chain's value is changed:

var chained = chaingun({}, {set: function(v) { return v * 10; }})
var chain = thing(2);
chain();  // 20

chain(3);
chain();  // 30

obj's properties can be accessed directly from the chainable:

var obj = {
  foo: 2,
  bar: 3,
  baz: {},
  quux: function() {}
};

var chained = chaingun(obj);
chained.foo === obj.foo;  // true
chained.bar === obj.bar;  // true
chained.baz === obj.baz;  // true
chained.quux === obj.quux;  // true