namespace
Library provides an API for creating sets of namespaced properties for any given objects (frozen or not). This effectively may be used for creating fields that are not part of object's public API, which is useful for hiding internal details or for adding fields to an existing objects (Built-ins or not) without mutating them and there for any risks of naming conflicts.
Usage
It is recommended to use this library with enabled WeakMap
s. On node that
simply means running it with additional flag: node --harmony_weakmaps
. If
weak maps are not available library will fallback to using imperfect weak map
shim.
var ns = require('namespace/core').ns
var internals = ns()
internals(publicAPI).secret = secret
Namespace may be used with multiple objects:
var observable = ns()
function Observable() {
observable(this).observers = []
}
Observable.prototype.observe = function(observer) {
observable(this).observers.push(observer)
}
Also, multiple namespaces can be used with a same object without any conflicts.
var pending = ns()
function Eventual() {
Observable.call(this)
pending(this).realized = false
}
Eventual.prototype = Object.create(Observable.prototype)
Eventual.prototype.realize = function realize(value) {
if (!pending(this).realized) {
obesrvable(this).observers.splice.forEach(function(observer) {
observer(value)
})
}
}
Access to the namespaced properties can be shared with other code by simple
handing a namespace function. Although doing this across modules is not
recommended, for example instead of sharing pending
namespace one could share
following function instead:
exports.isRealized = function isRealized(value) {
return pending(value).realized
}
Namespaced objects create parallel inheritance chain, or more simply:
var foo = ns()
var ancestor = {}
foo(ancestor) === foo(Object.create(ancestor)) // => true
Namespaces are simply a sugar on top of ES.next WeakMaps allowing you to associate sets of namespaced properties to an object via weak references.
Install
npm install namespace