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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 | |
}, | |
withdraw: { | |
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 () { | |
/* ... */ | |
}), | |
withdraw: 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 } | |
``` | |
### Installation | |
$ npm install d | |
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/) | |
### 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; }; | |
Object.defineProperties(Foo.prototype, autoBind({ | |
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 () {}; | |
Object.defineProperties(Foo.prototype, lazy({ items: d(function () { return []; }) })); | |
var foo = new Foo(); | |
foo.items.push(1, 2); // foo.items array created and defined directly on foo | |
``` | |
## Tests [](https://travis-ci.org/medikoo/d) | |
$ npm test | |
## Security contact information | |
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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