tooppoo / relegater

provide function which delegates a property access or method call to other object.

relegater

provide functions in order to delegate a property access or method call for base object to other.

Interfaces of the functions imitate delegate method in Ruby on Rails.

example

import { delegate, $delegate } from 'relegater';

const baseObj = {
  a: 1, b: 'b'
};
const delegated = {
  c: () => 'c',
  d: {
    e: true
  }
};

// delegate() create new object.
// no update to base object exist.
var result = delegate(baseObj).to(delegated, 'c', 'd').self;

result.a // 1
result.b // 'b'
result.c() // 'c'
result.d.e // true

baseObj.a // 1
baseObj.b // 'b'
baseObj.c // undefined
baseObj.d // undefined

// $delegate() modify base object destructively.
$delegate(baseObj).to(delegated, 'c', 'd');

baseObj.a // 1
baseObj.b // 'b'
baseObj.c() // 'c'
baseObj.d.e // true

baseObj is a object which receive actually property accesses or method calls.

when you want to delegate reference for baseObj to other, you should pass baseObj to delegate() or $delegate().

delegate()

delegate() create a new object which extends baseObj.

this function don't modify baseObj, so you use the created object instead of baseObj.

you can get the object from delegate({}).self.

$delegate()

$delegate() modify baseObj directly and destructively, but not modify prototype of baseObj.

how to delegate

delegate()/$delegate() return object which has following property.

• to(delegated, prop1, prop2, ... propX)

  this method return a new object which has same interface. this method can chain. when a property is specified twice in the method chain, later is preferred.

  delegated is a object which baseObj delegate some property accesses or method calls to.

  • delegated must be object. if this is not object, runtime error raise.

  • prop1~X is variable arguments. each prop is string which presents property name in delegated;

    if propX does not exist in delegated, it is ignored.

• self this property exist only when you use delegate().

  this object base on baseObj and has all properties which are specified by to().

License

MIT License