BMS Table Loader Library

This is a TypeScript library for loading BMS tables from a URL.

The types indicate what must be present for a BMS Table to be valid. Anything else might/will be something completely unexpected. You should handle these extensions yourself.

You can install it with your preferred NodeJS package manager:

# npm
npm install bms-table-loader

# yarn
yarn add bms-table-loader

# pnpm
pnpm add bms-table-loader

API

import { Loader } from "bms-table-loader";

const table = await Loader("http://nekokan.dyndns.info/~lobsak/genocide/insane.html");
// { head: ..., body: [...] }

table.body

Although table.head is kept identical, table.body entries are wrapped in some information about their checksum.

Recent developments in the BMS ecosystem have resulted in people spitting out sha256 styled entries, like:

• { sha256: "769359ebb55d3d6dff3b5c6a07ec03be9b87beda1ffb0c07d7ea99590605a732", md5: "", level: 1 }
• { sha256: "769359ebb55d3d6dff3b5c6a07ec03be9b87beda1ffb0c07d7ea99590605a732", md5: "null", level: 1 }.
• { sha256: "769359ebb55d3d6dff3b5c6a07ec03be9b87beda1ffb0c07d7ea99590605a732", level: 1 }.

This means it's no longer possible to just use md5 to identify a chart, and this requires some more complex validation (as sha256 is - too - an optional property with type unknown).

A table body.json of

[{
	"title": "example song 1",
	"level": "1",
	"md5": "935ac8a2d9a3e2307a6e0206f87c22ad",
	"sha256": "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56",
},
{
	"title": "example song 2",
	"level": "1",
	"sha256": "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56",
},
{
	"title": "example song 3",
	"level": "1",
	"md5": null,
	"sha256": "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56",
},
{
	"title": "example song 3",
	"level": "1",
	"md5": "null",
	"sha256": "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56",
}]

will result in table.body being

[
	{
		checksum: { type: "md5", value: "935ac8a2d9a3e2307a6e0206f87c22ad" },
		content: {
			title: "example song 1",
			level: "1",
			md5: "935ac8a2d9a3e2307a6e0206f87c22ad",
			sha256: "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56",
		},
	},
	{
		checksum: { type: "sha256", value: "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56" },
		content: {
			title: "example song 2",
			level: "1",
			sha256: "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56",
		},
	},
	{
		checksum: { type: "sha256", value: "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56"},
		content: {
			title: "example song 3",
			level: "1",
			md5: null,
			sha256: "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56",
		}
	},
	{
		checksum: { type: "sha256", value: "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56" },
		content: {
			title: "example song 3",
			level: "1",
			md5: "null",
			sha256: "5b7cbf452689aa56410c753cd48390df1dceaf723944d0023e352eaea3a2bf56",
		}
	}
]

Due to the complexities involved in determining how a chart was hashed, the convenience of pre-wrapping every chart with its checksum information outweigh the additional boilerplate needed.

If you want the body with no wrapping, see table.getRawBody().

getLevelOrder()

Returns the levels in this table in order. This is a utility method because there's three possible ways and places this can be defined in a BMS Table. Good fun.

getRawBody()

Returns the content of the BMS Tables' body.json without any checksum information - so exactly as it was sent over the wire (with invalid entries removed).

Library

We use PNPM as our package manager. Use pnpm install to install dependencies.

Build Script

We use TypeScript. This means you have to run pnpm build to compile the library up into something usable by node.

NOTE: This does not have to be done if running tests or if you use ts-node.

Tests

To run the tests, use pnpm test.

We use Node TAP as our test runner.

The tests are extremely lazy "can we load tables off the internet" style. I'm lazy.