Netsi Address Component

A fully encapsulated, zero-dependency web component for simple and robust Danish address lookup using Dataforsyningen's DAWA API. This component is written in TypeScript and provides strong typing for all configurations.

It is designed as a "headless" controller that attaches to your existing form fields, making it extremely flexible to integrate into any project.

Features

• Headless & Flexible: Attaches to any form structure using CSS selectors.
• TypeScript First: Provides strong types for configuration and API responses.
• Smart Defaults: Works out-of-the-box with a standard set of element IDs. No configuration needed for a basic setup.
• Advanced Data Mapping: Use a mapper function to transform API data before it's displayed in your UI.
• Zero Dependencies: Compiles to a single, dependency-free JavaScript file.
• Configurable: Easily configured, including all DAWA API parameters.
• Fuzzy Search: Optionally falls back to a "fuzzy" search if no exact matches are found.
• Keyboard Navigation: Full support for ArrowUp, ArrowDown, Enter, and Escape.
• Tested: Includes a suite of unit tests for core logic.

Demo

A local demo is available in the /demo directory. To run it, you first need to build the component from its TypeScript source.

# First, install Deno: https://deno.com/manual/getting_started/installation
# Then, build the project:
deno task build

# Serve the demo folder
npx http-server -o demo/index.html

Installation

Via JSR (Recommended)

deno add @netsi/address-component

Via NPM

npm install @netsi/address-component

Via CDN

The component's source is TypeScript, so direct use in the browser requires a build step. For CDN usage, it's recommended to use a service that transpiles and bundles JSR packages, like esm.sh.

<script type="module">
  // The 'netsi-address' element is automatically defined.
  import "https://esm.sh/jsr/@netsi/address-component";
</script>

Usage

1. Basic Usage (with Default Selectors)

If your form fields follow a simple ID convention, you can use the component with minimal configuration.

HTML:

<!-- The standalone component tag -->
<netsi-address id="address-component"></netsi-address>

<!-- Your form with the default IDs -->
<div class="form-group">
  <label for="address">Search for a Danish address</label>
  <!-- The component defaults to looking for an input with id="address" -->
  <input type="text" id="address" placeholder="e.g., Rådhuspladsen 1, 1550">
</div>

<!-- Default fields to be populated -->
<input type="text" id="vejnavn" readonly>
<input type="text" id="husnr" readonly>
<input type="text" id="postnr" readonly>
<input type="text" id="postnrnavn" readonly>
<!-- ... etc. See full list of defaults below. -->

JavaScript:

import "@netsi/address-component";

const addressComponent = document.getElementById("address-component");
// Minimal config, as the component will use its smart defaults.
addressComponent.config = {
  useFuzzyFallback: true,
};

2. Advanced Usage (with Custom Selectors and Mappers)

For full control, provide a ui object in the configuration. You can specify custom selectors and use a mapper function to format the data.

HTML:

<netsi-address id="address-component"></netsi-address>

<input type="text" class="my-search-field">
<input type="text" class="my-road-name-field" readonly>
<div>
  <span>Address created on:</span>
  <strong id="created-date"></strong>
</div>

JavaScript:

import "@netsi/address-component";

const addressComponent = document.getElementById("address-component");

addressComponent.config = {
  // Component behavior
  useFuzzyFallback: true,

  // DAWA API Parameters
  postnr: "2100", // Filter all searches by a specific postal code

  // UI Mapping
  ui: {
    // --- This is mandatory for custom UI ---
    address: ".my-search-field",

    // --- Simple mapping ---
    "adgangsadresse.vejstykke.navn": ".my-road-name-field",

    // --- Advanced mapping with a mapper function ---
    "historik.oprettet": {
      selector: "#created-date",
      mapper: (isoDateString) => {
        if (!isoDateString) return "Unknown";
        // Format the date for better readability
        return new Date(isoDateString).toLocaleDateString("da-DK");
      },
    },
  },
};

Default UI Selectors

If the ui object is not provided, the component uses the following id selectors. The keys are dot-notation paths to the data in the DAWA API response.

Data Path	Default Selector
address (The search input)	#address
etage	#etage
dør	#doer
adgangsadresse.vejstykke.navn	#vejnavn
adgangsadresse.husnr	#husnr
adgangsadresse.postnummer.nr	#postnr
adgangsadresse.postnummer.navn	#postnrnavn
adgangsadresse.kommune.kode	#kommunekode
adgangsadresse.kommune.navn	#kommune

Development

This project uses Deno for development.

• To build the browser-compatible bundle for the demo:

  deno task build

  This command uses esbuild to compile src/netsi-address.ts into demo/netsi-address.bundle.js.

• To run the tests:

  deno task test

Events

The component emits a netsi-address:select event when an address is successfully selected. The event.detail property contains the complete address object from DAWA.

addressComponent.addEventListener("netsi-address:select", (event) => {
  console.log("Address selected:", event.detail);
});

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This package was added to JSR and NPM with the help of Cursor. A fully encapsulated web component for Danish address lookup using DAWA.