British Isles Grid Reference library
British grid references are those associated with reference system known as 'OSGB 1936 / British National Grid' (epsg:27700). Irish grid references are those associated with the reference sytem known as 'TM75 / Irish Grid' (epsg:29903). Channel Island grid references are derived from the UTM grid - 'WGS 84 / UTM zone 30N' using a shorthand method whereby the leading '30U' prefix is removed. This gives grid references for the Channel Islands with prefixes of 'WA' or 'WV'.
The bigr library is an NPM package and can be installed with NPM in the usual way, e.g:
npm install brc-atlas-bigr
Alternatively you can get the javscript builds from the GitHub repo or include them in code directly from a CDN, e.g:
API documentation and code examples
For details of the API, view the JSDoc API documentation.
There are also a number of working examples.