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# D - Property descriptor factory
_Originally derived from [es5-ext](https://github.com/medikoo/es5-ext) package._
Defining properties with descriptors is very verbose:
```javascript
var Account = function () {};
Object.defineProperties(Account.prototype, {
deposit: { value: function () {
/* ... */
}, configurable: true, enumerable: false, writable: true },
whithdraw: { value: function () {
/* ... */
}, configurable: true, enumerable: false, writable: true },
balance: { get: function () {
/* ... */
}, configurable: true, enumerable: false }
});
```
D cuts that to:
```javascript
var d = require('d');
var Account = function () {};
Object.defineProperties(Account.prototype, {
deposit: d(function () {
/* ... */
}),
whithdraw: d(function () {
/* ... */
}),
balance: d.gs(function () {
/* ... */
})
});
```
By default, created descriptor follow characteristics of native ES5 properties, and defines values as:
```javascript
{ configurable: true, enumerable: false, writable: true }
```
You can overwrite it by preceding _value_ argument with instruction:
```javascript
d('c', value); // { configurable: true, enumerable: false, writable: false }
d('ce', value); // { configurable: true, enumerable: true, writable: false }
d('e', value); // { configurable: false, enumerable: true, writable: false }
// Same way for get/set:
d.gs('e', value); // { configurable: false, enumerable: true }
```
### Other utilities
#### autoBind(obj, props) _(d/auto-bind)_
Define methods which will be automatically bound to its instances
```javascript
var d = require('d');
var autoBind = require('d/auto-bind');
var Foo = function () { this._count = 0; };
autoBind(Foo.prototype, {
increment: d(function () { ++this._count; });
});
var foo = new Foo();
// Increment foo counter on each domEl click
domEl.addEventListener('click', foo.increment, false);
```
#### lazy(obj, props) _(d/lazy)_
Define lazy properties, which will be resolved on first access
```javascript
var d = require('d');
var lazy = require('d/lazy');
var Foo = function () {};
lazy(Foo.prototype, {
items: d(function () { return []; })
});
var foo = new Foo();
foo.items.push(1, 2); // foo.items array created
```
## Installation
### NPM
In your project path:
$ npm install d
### Browser
You can easily bundle _D_ for browser with [modules-webmake](https://github.com/medikoo/modules-webmake)
## Tests [](https://travis-ci.org/medikoo/d)
$ npm test
|
