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# @turf/bbox
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@turf/bbox calculates bounding boxes for any GeoJSON object, including FeatureCollection. It efficiently computes the minimum and maximum coordinate extents in [minX, minY, maxX, maxY] format by iterating through all coordinates in the GeoJSON geometry. The library supports reusing existing bbox properties when available for performance optimization.
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## Package Information
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- **Package Name**: @turf/bbox
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- **Package Type**: npm
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- **Language**: TypeScript
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- **Installation**: `npm install @turf/bbox`
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## Core Imports
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```typescript
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import { bbox } from "@turf/bbox";
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```
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For CommonJS:
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```javascript
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const { bbox } = require("@turf/bbox");
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```
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Default import:
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```typescript
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import bbox from "@turf/bbox";
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```
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## Basic Usage
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```typescript
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import { bbox } from "@turf/bbox";
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import { lineString, polygon, featureCollection } from "@turf/helpers";
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// Calculate bbox for a LineString
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const line = lineString([[-74, 40], [-78, 42], [-82, 35]]);
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const lineBbox = bbox(line);
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// Result: [-82, 35, -74, 42]
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// Calculate bbox for a Polygon  
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const poly = polygon([[
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  [101.0, 0.0],
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  [101.0, 1.0],
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  [100.0, 1.0], 
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  [100.0, 0.0],
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  [101.0, 0.0]
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]]);
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const polyBbox = bbox(poly);
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// Result: [100, 0, 101, 1]
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// Calculate bbox for a FeatureCollection
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const fc = featureCollection([line, poly]);
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const fcBbox = bbox(fc);
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// Result: [-82, 0, -74, 42]
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```
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## Capabilities
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### Bounding Box Calculation
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Calculates the bounding box for any GeoJSON object, including FeatureCollection. Uses existing bbox property if available, or computes from coordinates.
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```typescript { .api }
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/**
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 * Calculates the bounding box for any GeoJSON object, including FeatureCollection.
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 * Uses geojson.bbox if available and options.recompute is not set.
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 * @param geojson - Any GeoJSON object (Feature, FeatureCollection, Geometry, GeometryCollection)
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 * @param options - Optional parameters
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 * @returns bbox extent in [minX, minY, maxX, maxY] order
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 */
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function bbox(
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  geojson: AllGeoJSON,
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  options?: {
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    recompute?: boolean;
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  }
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): BBox;
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```
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**Parameters:**
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- `geojson` (AllGeoJSON) - Any GeoJSON object to calculate bounds for
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- `options.recompute` (boolean, optional) - Whether to ignore existing bbox property and force recalculation. Default: false
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**Returns:** BBox array representing [minX, minY, maxX, maxY] coordinate extents
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**Usage Examples:**
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```typescript
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import { bbox } from "@turf/bbox";
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import { point, multiPolygon } from "@turf/helpers";
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// Point bbox
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const pt = point([102.0, 0.5]);
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const ptBbox = bbox(pt);
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// Result: [102, 0.5, 102, 0.5]
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// Force recalculation even if bbox exists
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const geojsonWithBbox = { ...pt, bbox: [0, 0, 0, 0] };
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const recomputedBbox = bbox(geojsonWithBbox, { recompute: true });
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// Result: [102, 0.5, 102, 0.5] (ignores existing bbox)
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// Use existing bbox for performance
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const existingBbox = bbox(geojsonWithBbox);
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// Result: [0, 0, 0, 0] (uses existing bbox property)
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// Empty bbox arrays are returned as-is
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const emptyBboxGeojson = { ...pt, bbox: [] };
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const emptyResult = bbox(emptyBboxGeojson);
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// Result: [] (returns existing empty bbox)
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```
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**Error Handling:**
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- Throws error for unknown geometry types (delegated to coordEach from @turf/meta)
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- Returns `[Infinity, Infinity, -Infinity, -Infinity]` for null geometries
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## Types
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```typescript { .api }
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/**
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 * Union type for all possible GeoJSON objects
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 */
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type AllGeoJSON = Feature | FeatureCollection | Geometry | GeometryCollection;
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/**
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 * Bounding box represented as [minX, minY, maxX, maxY]
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 */
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type BBox = [number, number, number, number];
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/**
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 * GeoJSON properties object
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 */
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type GeoJsonProperties = { [name: string]: any } | null;
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/**
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 * GeoJSON Feature object
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 */
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interface Feature<G extends Geometry | null = Geometry, P = GeoJsonProperties> {
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  type: "Feature";
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  geometry: G;
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  properties: P;
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  bbox?: BBox;
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}
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/**
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 * Collection of GeoJSON Feature objects
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 */
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interface FeatureCollection<G extends Geometry | null = Geometry, P = GeoJsonProperties> {
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  type: "FeatureCollection";
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  features: Feature<G, P>[];
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  bbox?: BBox;
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}
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/**
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 * Base interface for all geometry types
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 */
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interface Geometry {
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  type: string;
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  bbox?: BBox;
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}
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/**
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 * Collection of geometry objects
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 */
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interface GeometryCollection {
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  type: "GeometryCollection";
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  geometries: Geometry[];
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  bbox?: BBox;
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}
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```