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## KDBush A very fast static spatial index for 2D points based on a flat KD-tree. Compared to [RBush](https://github.com/mourner/rbush): - **Points only** — no rectangles. - **Static** — you can't add/remove items after initial indexing. - **Faster** indexing and search, with lower **memory** footprint. - Index is stored as a single **array buffer** (so you can [transfer](https://developer.mozilla.org/en-US/docs/Glossary/Transferable_objects) it between threads or store it as a compact file). If you need a static index for rectangles, not only points, see [Flatbush](https://github.com/mourner/flatbush). When indexing points, KDBush has the advantage of taking ~2x less memory than Flatbush. [](https://github.com/mourner/kdbush/actions) [](https://github.com/mourner/projects) ## Usage ```js // initialize KDBush for 1000 items const index = new KDBush(1000); // fill it with 1000 points for (const {x, y} of items) { index.add(x, y); } // perform the indexing index.finish(); // make a bounding box query const foundIds = index.range(minX, minY, maxX, maxY); // map ids to original items const foundItems = foundIds.map(i => items[i]); // make a radius query const neighborIds = index.within(x, y, 5); // instantly transfer the index from a worker to the main thread postMessage(index.data, [index.data]); // reconstruct the index from a raw array buffer const index = KDBush.from(e.data); ``` ## Install Install with NPM: `npm install kdbush`, then import as a module: ```js import KDBush from 'kdbush'; ``` Or use as a module directly in the browser with [jsDelivr](https://www.jsdelivr.com/esm): ```html <script type="module"> import KDBush from 'https://cdn.jsdelivr.net/npm/kdbush/+esm'; </script> ``` Alternatively, there's a browser bundle with a `KDBush` global variable: ```html <script src="https://cdn.jsdelivr.net/npm/kdbush"></script> ``` ## API #### new KDBush(numItems[, nodeSize, ArrayType]) Creates an index that will hold a given number of points (`numItems`). Additionally accepts: - `nodeSize`: Size of the KD-tree node, `64` by default. Higher means faster indexing but slower search, and vise versa. - `ArrayType`: Array type to use for storing coordinate values. `Float64Array` by default, but if your coordinates are integer values, `Int32Array` makes the index faster and smaller. #### index.add(x, y) Adds a given point to the index. Returns a zero-based, incremental number that represents the newly added point. #### index.range(minX, minY, maxX, maxY) Finds all items within the given bounding box and returns an array of indices that refer to the order the items were added (the values returned by `index.add(x, y)`). #### index.within(x, y, radius) Finds all items within a given radius from the query point and returns an array of indices. #### `KDBush.from(data)` Recreates a KDBush index from raw `ArrayBuffer` data (that's exposed as `index.data` on a previously indexed KDBush instance). Very useful for transferring or sharing indices between threads or storing them in a file. ### Properties - `data`: array buffer that holds the index. - `numItems`: number of stored items. - `nodeSize`: number of items in a KD-tree node. - `ArrayType`: array type used for internal coordinates storage. - `IndexArrayType`: array type used for internal item indices storage.