mrpack-js

Utility to parse and edit .mrpack (Modrinth Modpack) Files

Usage

This utility can be used to, for example, merge two modpacks together or dynamically generate your modpacks.

Examples

Typescript should tell you what types you can use

import * as mr from 'mrpack-js'
import fs from 'node:fs/promises'
import fsSync from 'node:fs'
import { Client } from 'mrpack-js/mrindex';

let pack = await mr.initPack();
let packFile = await fs.readFile("./Cobblemon Modpack [Fabric] 1.4.1.mrpack");

await pack.unpack(packFile);

// TODO: Make your changes

console.log(pack.mrpack); // look at a modpack json to understand how this works

pack.mrpack?.files.push({
    path: "mods/test.jar",
    hashes: {
        "sha1": "xxx",
        "sha512": "xxx",
    },
    env: {
        "client": "optional" as Client,
        "server": "required" as Client
    },
    downloads: [],
    fileSize: 0
});

pack.overrides.push({
    file: Buffer.from("This is a test file!\nwith two lines, wow /:_:/"), // string = file path | Buffer = file contents | ReadStream = file contents;
    path: "test.txt" // path in modpack
});

// END: Changes

let outFile = fsSync.createWriteStream("./output.mrpack");

await pack.pack(outFile);
await pack.cleanup();

Types

export type Override = {
    file: string | Buffer | ReadStream;
    path: string;
};

export class MRPack {

    private tmp_dir: string;
    public mrpack?: MRIndex;
    public overrides: Override[];

    async pack(destStream: WriteStream);
    async unpack(file: compressing.sourceType);

    cleanup();
    cleanupSync();

}

export interface MRIndex {
    game:          string;
    formatVersion: number;
    versionId:     string;
    name:          string;
    summary:       null;
    files:         File[];
    dependencies:  object;
}

export interface File {
    path:      string;
    hashes:    object;
    env:       Env;
    downloads: string[];
    fileSize:  number;
}

export interface Env {
    server: Client;
    client: Client;
}

export enum Client {
    Optional = "optional",
    Required = "required",
}

Install

To install dependencies:

(also works with npm, pnpm, yarn, etc...)

bun install

To run:

bun run index.ts

This project was created using bun init in bun v1.0.0. Bun is a fast all-in-one JavaScript runtime.