---
title: "FeatureIdentifier | JavaScript maps SDK"
description: "Documentation for MapTiler SDK"
---

> For AI agents: a documentation index is available at [/llms.txt](https://docs.maptiler.com/llms.txt). Markdown versions of all pages are available by appending .md to any URL.

# Type Alias FeatureIdentifier

A feature identifier that is bound to a source

type FeatureIdentifier \= {  
    [id](#id)?: string | number;  
    [source](#source): string;  
    [sourceLayer](#sourcelayer)?: string;  
}

##### Index

### Properties[](#properties)

[id?](#id) [source](#source) [sourceLayer?](#sourcelayer)

## Properties[](#properties-1)

### `Optional`id[](#id)

id?: string | number

Unique id of the feature.

### source[](#source)

source: string

The id of the vector or GeoJSON source for the feature.

### `Optional`sourceLayer[](#sourcelayer)

sourceLayer?: string

_For vector tile sources, `sourceLayer` is required._