define-accessor-property/README.md

Define an accessor property on an object. Will either throw, or fall back to assignment in loose mode, in an engine without descriptors.

# define-accessor-property <sup>[![Version Badge][npm-version-svg]][package-url]</sup>

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Define an accessor property on an object. In an engine without descriptors, in loose mode, when only a getter is provided, nonEnumerable is false, and nonConfigurable is false, wil fall back to assignment - otherwise, it will throw.

The two `non*` options can also be passed `null`, which will use the existing state if available.

The `loose` option will mean that if you attempt to set a nonconfigurable/nonwritable accessor property with `set`, in an environment without descriptor support, it will fall back to normal assignment (and eagerly evaluate the getter).

## Usage

```javascript
var defineAccessorProperty = require('define-accessor-property');
var assert = require('assert');

var str = 'value';
var strThunk = function () { return str; };
var strSetter = function (v) { str = v; };
var random = function () { return Math.random(); };

var obj = {};
defineAccessorProperty(
	obj,
	'key',
	{
		get: strThunk,
		set: strSetter,
	}
);
defineAccessorProperty(
	obj,
	'key2',
	{
		get: random, // at least one of "get" or "set" must be provided
		nonConfigurable: true, // optional
		nonEnumerable: true, // optional
		loose: false, // optional
	}
);

assert.deepEqual(
	Object.getOwnPropertyDescriptors(obj),
	{
		key: {
			configurable: true,
			enumerable: true,
			get: strThunk,
			set: strSetter,
		},
		key2: {
			configurable: false,
			enumerable: false,
			get: random,
			set: undefined,
		},
	}
);
```

[package-url]: https://npmjs.org/package/define-accessor-property
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[dev-deps-url]: https://david-dm.org/ljharb/define-accessor-property#info=devDependencies
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[license-image]: https://img.shields.io/npm/l/define-accessor-property.svg
[license-url]: LICENSE
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