jp-local-gov-id

JavaScript APIs for Japan’s nationwide local government codes (全国地方公共団体コード).

Data is not shipped as a single JSON blob. The data package publishes Brotli-compressed .bin.br files split by prefecture plus a hybrid n-gram search index, so clients can lazy-load only what they need.

Examples of what you can do

• List municipalities in a prefecture
• List all prefectures
• Get municipality counts per prefecture (sync; no per-prefecture load)
• Resolve codes for address normalization
• Nationwide string search (hybrid n-gram index narrows candidates first)

Install

npm install @b4moss/jp-local-gov-id @b4moss/jp-local-gov-id-data

See Installation for details.

Quick example

import { createLocalGovClient } from "@b4moss/jp-local-gov-id";
import dataset from "@b4moss/jp-local-gov-id-data";

const client = await createLocalGovClient({ data: dataset });
await client.getByCode("131016"); // Chiyoda

See Usage for more.

Try it

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Questions / requests

Please open a GitHub Issue.