pd

pd

Helping you do prototypical OO

Status: production ready

Example

var extend = require("pd").extend

var Animal = {
    legs: 4,
    walk: function () { ... }
}

var Cat = extend({}, Animal, {
    nyan: function () { ... },
    constructor: function () { 
        this.lives = 9
        return this;
    }
});

var cat = extend({}, Cat).constructor()

Motivation

ES5 OO is verbose

pd solves this with utilities and sugar.

Blog Posts

• Improving ES5 OO
• Doing OO JS part 3
• Doing OO JS part 2
• Doing Object Oriented JavaScript

Documentation

pd (obj)

pd converts all the values of your objects properties into property descriptors of those values.

pd({
    "foo": "bar"
})

is the same as

{
    "foo": {
        "value": "bar",
        "enumerable": true,
        "writable": true,
        "configurable": true
    }
}

pd.extend (obj..)

pd.extend extends an object with other objects. key clashes are given right preference

pd.extend(
    {
        "one": "faz",
        "three": "bar"
    },
    {
        "two": "ni",
        "three": "baz"
    },
    {
        "three": "bas",
        "four": "four"
    }
);

is the same as

{
    "one": "faz",
    "two": "ni",
    "three": "bas",
    "four": "four"
}

pd.extend returns the first object you pass in.

pd.bindAll (obj..)

pd.bindAll is similar to underscore's bindAll method. It takes an object and binds all it's methods to the object. It takes an optional list of objects to mix in

var o = {
    constructor: function () { 
        pd.bindAll(this, {
            draw: function () { 
                /* use `this` with its "correct" value, i.e. `o` */
            }
        });
    },
    start: function (eventEmitter) {
        // note `this.draw` would not work correctly if it wasn't bound
        eventEmitter.on("draw", this.draw);
    }
};

pd.Name

pd.Name constructs a Name function. This name function when passed your object will return a privates object. This privates object cannot be accessed in any other way then calling Name.

var Klass = (function () {
    var privates = pd.Name();

    return {
        constructor: function (secret) {
            privates(this).secret = secret;
        },
        getSecret: function () {
            return privates(this).secret;
        }
    };
}());

pd.memoize(fn[, context[, hasher]]

pd.memoize caches the results of an asynchronous function. Pass in an optional context so the fn is called with the context and pass in an optional hasher so you can choose how your the arguments of the returned memoized function should map to results

var f = pd.memoize(asyncFunction),
    start = Date.now()

f(10)
f(10)
f(10)

var time_taken = Date.now() - start // roughly 500
// because asyncFunction is memoized, the second and third call return
// at the same time as the first, and any call after that returns
// immediately

function asyncFunction(key, callback) {
    setTimeout(function () {
        callback(key * 2)
    }, 500)
}

Installation

npm install pd

Test

make test

Contributors

• Raynos
• Gozala

MIT Licenced