define-properties
DefinitelyTyped icon, indicating that this package has TypeScript declarations provided by the separate @types/define-properties package

1.2.1 • Public • Published

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Define multiple non-enumerable properties at once. Uses Object.defineProperty when available; falls back to standard assignment in older engines. Existing properties are not overridden. Accepts a map of property names to a predicate that, when true, force-overrides.

Example

var define = require('define-properties');
var assert = require('assert');

var obj = define({ a: 1, b: 2 }, {
	a: 10,
	b: 20,
	c: 30
});
assert(obj.a === 1);
assert(obj.b === 2);
assert(obj.c === 30);
if (define.supportsDescriptors) {
	assert.deepEqual(Object.keys(obj), ['a', 'b']);
	assert.deepEqual(Object.getOwnPropertyDescriptor(obj, 'c'), {
		configurable: true,
		enumerable: false,
		value: 30,
		writable: false
	});
}

Then, with predicates:

var define = require('define-properties');
var assert = require('assert');

var obj = define({ a: 1, b: 2, c: 3 }, {
	a: 10,
	b: 20,
	c: 30
}, {
	a: function () { return false; },
	b: function () { return true; }
});
assert(obj.a === 1);
assert(obj.b === 20);
assert(obj.c === 3);
if (define.supportsDescriptors) {
	assert.deepEqual(Object.keys(obj), ['a', 'c']);
	assert.deepEqual(Object.getOwnPropertyDescriptor(obj, 'b'), {
		configurable: true,
		enumerable: false,
		value: 20,
		writable: false
	});
}

Tests

Simply clone the repo, npm install, and run npm test

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Install

npm i define-properties

Weekly Downloads

36,550,093

Version

1.2.1

License

MIT

Unpacked Size

12.9 kB

Total Files

9

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Collaborators

  • ljharb