# @turf/invariant

# getCoord

Unwrap a coordinate from a Point Feature, Geometry or a single coordinate.

**Parameters**

-   `obj` **([Array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array)<any> | [Geometry](http://geojson.org/geojson-spec.html#geometry) \| [Feature](http://geojson.org/geojson-spec.html#feature-objects)<[Point](http://geojson.org/geojson-spec.html#point)>)** any value

Returns **[Array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array)<[number](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number)>** coordinates

# getCoords

Unwrap coordinates from a Feature, Geometry Object or an Array of numbers

**Parameters**

-   `obj` **([Array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array)<any> | [Geometry](http://geojson.org/geojson-spec.html#geometry) \| [Feature](http://geojson.org/geojson-spec.html#feature-objects)<any>)** any value

Returns **[Array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array)<any>** coordinates

# geojsonType

Enforce expectations about types of GeoJSON objects for Turf.

**Parameters**

-   `value` **GeoJSON** any GeoJSON object
-   `type` **[string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)** expected GeoJSON type
-   `name` **[string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)** name of calling function


-   Throws **[Error](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error)** if value is not the expected type.

# featureOf

Enforce expectations about types of [Feature](http://geojson.org/geojson-spec.html#feature-objects) inputs for Turf.
Internally this uses [geojsonType](#geojsontype) to judge geometry types.

**Parameters**

-   `feature` **[Feature](http://geojson.org/geojson-spec.html#feature-objects)** a feature with an expected geometry type
-   `type` **[string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)** expected GeoJSON type
-   `name` **[string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)** name of calling function


-   Throws **[Error](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error)** error if value is not the expected type.

# collectionOf

Enforce expectations about types of [FeatureCollection](http://geojson.org/geojson-spec.html#feature-collection-objects) inputs for Turf.
Internally this uses [geojsonType](#geojsontype) to judge geometry types.

**Parameters**

-   `featureCollection` **[FeatureCollection](http://geojson.org/geojson-spec.html#feature-collection-objects)** a FeatureCollection for which features will be judged
-   `type` **[string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)** expected GeoJSON type
-   `name` **[string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)** name of calling function


-   Throws **[Error](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error)** if value is not the expected type.

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---

This module is part of the [Turfjs project](http://turfjs.org/), an open source
module collection dedicated to geographic algorithms. It is maintained in the
[Turfjs/turf](https://github.com/Turfjs/turf) repository, where you can create
PRs and issues.

### Installation

Install this module individually:

```sh
$ npm install @turf/invariant
```

Or install the Turf module that includes it as a function:

```sh
$ npm install @turf/turf
```