D

Property descriptor factory

Originally derived from es5-ext package.

Defining properties with descriptors is very verbose:

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:

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:

{ configurable: true, enumerable: false, writable: true }

You can overwrite it by preceding value argument with instruction:

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, Webmake or Webpack

Other utilities

autoBind(obj, props) (d/auto-bind)

Define methods which will be automatically bound to its instances

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

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

$ npm test

Security contact information

To report a security vulnerability, please use the Tidelift security contact. Tidelift will coordinate the fix and disclosure.

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