@molecule/api-geolocation-nominatim

Auto-generated, AI-first package reference for the molecule.dev ecosystem. It is written to be read by coding agents as much as by people, and is generated from this package's source — edit src/index.ts JSDoc, not this file.

Nominatim (OpenStreetMap) geolocation provider for molecule.dev.

Implements the GeolocationProvider interface using the Nominatim API for geocoding, reverse geocoding, and place search (autocomplete). Distance calculations use the Haversine formula. Timezone lookups are not supported.

Quick Start

import { setProvider } from '@molecule/api-geolocation'
import { provider } from '@molecule/api-geolocation-nominatim'

setProvider(provider)

Type

provider

Installation

npm install @molecule/api-geolocation-nominatim @molecule/api-geolocation

API

Interfaces

NominatimGeolocationConfig

Configuration options for the Nominatim geolocation provider.

interface NominatimGeolocationConfig {
  /**
   * A valid HTTP `User-Agent` header identifying the application.
   * Required by the Nominatim Usage Policy for the public instance.
   * Self-hosted instances may not require this.
   */
  userAgent: string

  /** BCP 47 language code for results (e.g., `'en'`, `'fr'`). */
  language?: string

  /** ISO 3166-1 alpha-2 country codes to restrict results to (e.g., `['US', 'CA']`). */
  countryCodes?: string[]

  /** Request timeout in milliseconds. Defaults to `10000`. */
  timeout?: number

  /**
   * Base URL override for self-hosted Nominatim instances.
   * Defaults to `'https://nominatim.openstreetmap.org'`.
   */
  baseUrl?: string

  /**
   * Email address to include in requests (requested by the Nominatim Usage Policy
   * for heavy usage of the public instance).
   */
  email?: string

  /** Maximum number of results to return from search queries. Defaults to `10`. */
  limit?: number
}

Functions

createProvider(config)

Creates a Nominatim geolocation provider.

function createProvider(config: NominatimGeolocationConfig): GeolocationProvider

• config — Provider configuration including the User-Agent string.

Returns: A GeolocationProvider backed by the Nominatim API.

Constants

provider

The provider implementation, lazily initialized from env: NOMINATIM_USER_AGENT (identifying User-Agent — the 'molecule-app' default is not policy-compliant for production), NOMINATIM_EMAIL (usage-policy contact), and NOMINATIM_BASE_URL (self-hosted instance).

const provider: GeolocationProvider

Core Interface

Implements @molecule/api-geolocation interface.

Bond Wiring

Setup function to register this provider with the core interface:

import { setProvider } from '@molecule/api-geolocation'
import { provider } from '@molecule/api-geolocation-nominatim'

export function setupGeolocationNominatim(): void {
  setProvider(provider)
}

Injection Notes

Requirements

Peer dependencies:

• @molecule/api-geolocation ^1.0.1

Runtime Dependencies

• @molecule/api-geolocation

• The public nominatim.openstreetmap.org server enforces a strict usage policy: max 1 request/second, no autocomplete-as-you-type, and an identifying User-Agent. Debounce autocomplete() aggressively (or trigger it on submit, not keystrokes), set NOMINATIM_USER_AGENT to a string that identifies YOUR app (the 'molecule-app' default is not compliant for production), and set NOMINATIM_EMAIL as the policy contact. Violations get the app's traffic blocked.

• For production volume, self-host Nominatim and point NOMINATIM_BASE_URL (or config.baseUrl) at it — the public-server limits then don't apply.

• getTimezone is not implemented (optional core capability) — feature- detect per the core's remarks, or use @molecule/api-geolocation-google.

E2E Tests

Integration checklist — drive the real UI (live preview, no mocks), adapt each item to this app's actual screens/flows, and check every box off one by one. A box you can't check is an integration bug to fix — not a skip:

• A known input resolves to plausibly-correct results: a real address passed to geocode() returns coordinates in roughly the right place (a famous landmark lands inside its own city, not the middle of the ocean), and a known lat/lng passed to reverseGeocode() names the right city — never an empty array, null, 0,0, or a hardcoded placeholder.
• The app actually CONSUMES the result downstream, verified on screen: the map recenters on the geocoded point, a "near me" list is sorted or filtered by distance() (closest first), or the address form marks a real address valid and a bogus one invalid — a coordinate that comes back but changes nothing in the UI is a broken integration, not a pass.
• If the app relies on the BROWSER geolocation permission, denying it (or letting it time out) falls back gracefully to manual entry — type or autocomplete an address — never a blank map, a spinner that never resolves, or a crash.
• An unresolvable input (gibberish address, empty geocode()/ reverseGeocode() result) surfaces a clear "location not found" message, not a crash, a silent blank screen, or a default location shown as if real.
• PRIVACY: a user's precise coordinates are not exposed to other users or written to logs beyond what the feature needs (persist/show only the granularity required — e.g. city, not raw lat/lng), and the geocoding provider key stays SERVER-SIDE (app screens call YOUR API, never the geocoding service directly).