Macroable

Macroable is a small ES6 class that can be extended to add functionality of macros and getters to your own class.

It is helpful if you want to expose an API to get your classes extended.

This library is used by AdonisJs to offer extend interface for core class.

Installation

As always, pull it from npm.

npm i --save macroable

Usage

const Macroable = require('macroable')

class User extends Macroable {

}

// it's required to define empty objects for macros and getters.
User._macros = {}
User._getters = {}

Once your class extends Macroable class, it get's a bunch of static methods to define macros and getters.

Using Macros

User.macro('getUsers', function () {
  // do some work
})

and now you can use the method from the class instance.

const user = new User()
user.getUsers()

Using Getters

Getters are values evaluated everytime someone access them.

User.getter('username', function () {
    // return username
})

and now you can use the property from the class instance

const user = new User()
user.username

Singleton Getters

Calling the getter callback everytime may be unrequired, since you do not want to re-compute the values. A singleton getter can also be defined.

User.getter('username', function () {
    // I am only called once
}, true)

const user = new User()

user.username // invokes callback and caches value
user.username // returns from cache

Hydrating Class

If for some reason you want to remove all getters and macros, you can call the hydrate method.

User.macro('getUsers', callback)

User.hasMacro('getUsers') // true

User.hydrate()

User.hasMacro('getUsers') // false

Checking Existence

You can also find whether a getter or macro already exists or not.

User.hasMacro('getUsers')
User.hasGetter('username')