OS Grid Reference to WGS84 Conversion

GPT-5 vibecoded conversion from UK Ordnance Survey Grid References to and from WGS84 coordinate system.

No external script dependencies or API lookups.

Share and enjoy.

To install dependencies:

bun install

To run tests:

bun run test

To transpile TypeScript:

bun run tsc

To convert from OS Grid Reference to WGS84 latitude,longitude:

const { lat, lon } = gridRefToWgs84("TL 44982 57869");

To convert from WGS84 latitude,longitude to OS Grid Reference:

const gridRef = wgs84ToGridRef(50.805547, -0.037451998);