135 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			135 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
# D
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## Property descriptor factory
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_Originally derived from [es5-ext](https://github.com/medikoo/es5-ext) package._
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Defining properties with descriptors is very verbose:
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```javascript
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var Account = function () {};
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Object.defineProperties(Account.prototype, {
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  deposit: {
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    value: function () {
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      /* ... */
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    },
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    configurable: true,
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    enumerable: false,
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    writable: true
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  },
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  withdraw: {
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    value: function () {
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      /* ... */
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    },
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    configurable: true,
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    enumerable: false,
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    writable: true
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  },
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  balance: {
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    get: function () {
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      /* ... */
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    },
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    configurable: true,
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    enumerable: false
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  }
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});
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```
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D cuts that to:
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```javascript
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var d = require("d");
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var Account = function () {};
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Object.defineProperties(Account.prototype, {
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  deposit: d(function () {
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    /* ... */
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  }),
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  withdraw: d(function () {
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    /* ... */
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  }),
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  balance: d.gs(function () {
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    /* ... */
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  })
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});
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```
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By default, created descriptor follow characteristics of native ES5 properties, and defines values as:
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```javascript
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{ configurable: true, enumerable: false, writable: true }
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```
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You can overwrite it by preceding _value_ argument with instruction:
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```javascript
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d("c", value); // { configurable: true, enumerable: false, writable: false }
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d("ce", value); // { configurable: true, enumerable: true, writable: false }
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d("e", value); // { configurable: false, enumerable: true, writable: false }
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// Same way for get/set:
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d.gs("e", value); // { configurable: false, enumerable: true }
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```
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### Installation
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    $ npm install d
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To port it to Browser or any other (non CJS) environment, use your favorite CJS bundler. No favorite yet? Try: [Browserify](http://browserify.org/), [Webmake](https://github.com/medikoo/modules-webmake) or [Webpack](http://webpack.github.io/)
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### Other utilities
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#### autoBind(obj, props) _(d/auto-bind)_
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Define methods which will be automatically bound to its instances
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```javascript
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var d = require('d');
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var autoBind = require('d/auto-bind');
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var Foo = function () { this._count = 0; };
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Object.defineProperties(Foo.prototype, autoBind({
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  increment: d(function () { ++this._count; });
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}));
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var foo = new Foo();
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// Increment foo counter on each domEl click
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domEl.addEventListener('click', foo.increment, false);
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```
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#### lazy(obj, props) _(d/lazy)_
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Define lazy properties, which will be resolved on first access
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```javascript
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var d = require("d");
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var lazy = require("d/lazy");
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var Foo = function () {};
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Object.defineProperties(Foo.prototype, lazy({ items: d(function () { return []; }) }));
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var foo = new Foo();
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foo.items.push(1, 2); // foo.items array created and defined directly on foo
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```
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## Tests [](https://travis-ci.org/medikoo/d)
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    $ npm test
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## Security contact information
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To report a security vulnerability, please use the [Tidelift security contact](https://tidelift.com/security). Tidelift will coordinate the fix and disclosure.
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---
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<div align="center">
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	<b>
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		<a href="https://tidelift.com/subscription/pkg/npm-d?utm_source=npm-d&utm_medium=referral&utm_campaign=readme">Get professional support for d with a Tidelift subscription</a>
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	</b>
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	<br>
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	<sub>
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		Tidelift helps make open source sustainable for maintainers while giving companies<br>assurances about security, maintenance, and licensing for their dependencies.
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	</sub>
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</div>
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