# obj-properties
> Dynamically evaluated collection of object properties
Latest version **0.2.2** (published 2016-12-11) · ISC license · 0 weekly downloads
## Install
```sh
npm install obj-properties
pnpm add obj-properties
yarn add obj-properties
bun add obj-properties
```
## Health
**Score 15/100 (F)** — status: abandoned.
Positive: no vulnerabilities.
Warnings: low downloads; no types; no esm support; pre 1.0.
Negative: abandoned; low maintenance score.
## Facts
| | |
|---|---|
| Version | 0.2.2 |
| Published | 2016-12-11 |
| First published | 2016-04-14 |
| Weekly downloads | 0 |
| License | ISC |
| TypeScript types | none |
| Module format | CommonJS |
| Dependencies | 4 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 1 |
| Author | Menelaus Perdikeas |
| Maintainers | marcusjuniusbrutus |
| Keywords | properties |
## Links
- npm: https://www.npmjs.com/package/obj-properties
- Repository: https://github.com/mperdikeas/js-object-properties
- Homepage: https://github.com/mperdikeas/js-object-properties#readme
- Issues: https://github.com/mperdikeas/js-object-properties/issues
- npm.io page: https://npm.io/package/obj-properties
## Dependencies (4)
- [eval](https://npm.io/package/eval.md) ^0.1.1
- [babel-polyfill](https://npm.io/package/babel-polyfill.md) ^6.7.4
- [babel-register](https://npm.io/package/babel-register.md) ^6.18.0
- [source-map-support](https://npm.io/package/source-map-support.md) ^0.4.0
## Recent versions
- 0.2.2 (latest) — 2016-12-11
- 0.2.1 — 2016-12-11
- 0.2.0 — 2016-12-11
- 0.1.17 — 2016-12-11
- 0.1.16 — 2016-12-11
- 0.1.15 — 2016-12-11
- 0.1.13 — 2016-06-10
- 0.1.12 — 2016-06-09
- 0.1.11 — 2016-06-09
- 0.1.10 — 2016-04-15
- 0.1.9 — 2016-04-15
- 0.1.8 — 2016-04-15
- 0.1.8-pre3 — 2016-04-15
- 0.1.8-pre2 — 2016-04-15
- 0.1.8-pre — 2016-04-15
- … 8 more at https://npm.io/package/obj-properties/versions
## README
obj-properties
=========
A small library allowing a user to specify which properties of an
object he's interested to retrieve by using arbitrary boolean expressions
based on the following predicates:
* **own**: whether the property lives on the object or up the prototype chain
* **symbol**: whether the property is a symbol or not
* **enumerable**: whether the property is enumerable or not
* **depth**: the "depth" of the object on which the property is located along the prototype chain.
0 corresponds to the object itself, 1 to its prototype, 2 to the prototype's prototype
and so on.
* **height**: the "height" of the object on which the property is located measured from the 'base'
of the prototype chain. I.e. 0 corresponds to the Object prototype.
Function *properties* is exported which returns, when called with an object argument,
an array of objects corresponding to that argument's properties. Objects are of the following kind:
```javascript
{
prop : // the name of the property
, value : // the value of that property
, object : // the object on which the property lives
// (can be the object itself or some prototype)
, depth : // the "depth" of the object on which the property is declared
// (0 for the object itself, 1 for its prototype)
, height : // the "height" of the object on which the property is declared
// (0 for the Object.prototype, 1 for its child, etc.)
, own : // whether the property is declared directly on the object passed as argument
// (this is equivalent to testing for depth===0)
, enumerable : // whether the property is enumerable
, symbol : // whether the propery is a symbol
}
```
Note: all of the above properties are exposed and can be used in the boolean predicate expressions except for *prop*,
*value* and *object*.
The function *properties* can be called with 1, 2 or 3 arguments:
```javascript
properties(o); // all properties of the object and its ancestors
// along the prototype chain are returned
properties(o, 'own && symbol && (depth == 3)'); // only properties satisfying the arbitrary
// boolean expression are returned
properties(o, 'some boolean expression', x=>x.prop) ; // as above, but only return the property
// names in the returned array
```
Effectively only the 1st argument is mandatory:
* the 2nd argument defaults to the string *'true'*
* the 3rd argument defaults to: *x=>x*
## Installation
npm install obj-properties --save
## Usage
```javascript
import {properties} from 'obj-properties';
// or:
// var properties = require('obj-properties').properties;
var o = {};
// evaluates to *all* properties along the prototype chain
properties(o);
// evaluates to an array of only non-symbol own properties of object o
properties(o, 'own && !symbol');
// evaluates to an array of all non-symbol properties of the object and
// its *immediate* ancestor only
properties(o, '(depth<=1) && !symbol');
// evaluates to an array of all non-symbol properties of an object o
// excepting only those that are defined in the Object.prototype
properties(o, '!symbol && (height>0)');
// like above, but only return the properties themselves, not the
// extra information
properties(o, '!symbol && (height>0)', x=>x.prop);
// return the non-enumerable properties of the object at the root
// of the prototype chain (the Object.prototype)
properties(o, '!enumerable && (height===0)', x=>x.prop);
// return the non-enumerable properties of the object (or any of
// its prototypes, except the Object.prototype)
properties(o, '(height>0) && (!enumerable)', x=>x.prop);
// helper function that only returns count:
import {propertiesCount} from 'obj-properties';
propertiesCount({}); // 12
propertiesCount({}, 'own'); // 0
```
## Tests
npm test
## Contributing
## Release History
* 0.1.0 Initial release
* 0.1.1 fixes
* 0.1.2 renamed 'enum' predicate to 'enumerable'
* 0.1.3 forgot to transpile
* 0.1.4 more examples in documentation
* 0.1.5-7 cosmetics and typos
* 0.1.8 babel-polyfill pattern with two files
* 0.1.9 cosmetic
* 0.1.10 cosmetic
* 0.1.11 added propertiesCount
* 0.1.12 dropped dead code
* 0.1.13 added testing
* 0.1.14 only conditionally requiring the Babel polyfill
* 0.1.15 fixed problem with running tests
* 0.1.16 fixed the "Reflect.ownKeys called on non-object" bug
* 0.1.17 returning property values as well
* 0.2.0 bumped version
* 0.2.1 test for arrays
* 0.2.2 text cosmetic
---
_Source: https://npm.io/package/obj-properties · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._