Launch settings

You can use Launcher to download and launch Minecraft, and Java to download and install Java Runtime.

Tip

To easily manage Minecraft versions, mod loaders, and modpacks, it is recommended to use the url option to connect your launcher to an EML AdminTool website. This way, you can manage all your Minecraft configurations from the AdminTool dashboard without changing your launcher’s code.

Launcher

import { Launcher, CrackAuth } from 'eml-lib'

launcher()

async function launcher() {
  const launcher = new Launcher({
    url: 'https://at.emlproject.com',
    root: 'eml',
    account: new CrackAuth().auth('GoldFrite') // CrackAuth for demo purpose only
  })

  try {
    await launcher.launch()
  } catch (err) {
    console.error(err)
  }
}

`Launcher` constructor

Parameter	Type	Description	Required?
`config`	`Config` (see below)	The configuration of the Launcher.	Yes

`Launcher.launch()` method

Launch Minecraft.

Note

This method will patch the Log4j vulnerability.

Throws: FETCH_ERROR - If a request to get data fails. • DOWNLOAD_ERROR - If a download fails. • EXEC_ERROR - If an execution fails.

Emits: See Events below.

`Config` object

Tip

Check the configuration generator to easily create a valid configuration for your launcher.

Field	Type	Description	Required?
`url`	`string`	The URL of your EML AdminTool instance. Provides modpack manifest and server settings. Attention! Ignored if a Minecraft version is defined in `minecraft.version` or `profile.minecraft.version`. Defaults to latest Vanilla if no URL/version is provided.	No
`profile`	`IProfile`	The specific profile to launch. Recommended to retrieve via `Profiles.getProfiles()`. Attention! In agnostic mode (no `url`), the profile must have a valid `slug` for folder naming.	No
`profile.minecraft`	`object`	Instance-specific Minecraft configuration. Attention! Takes precedence over root `minecraft` config and AdminTool data.	No defaults to `{ version: undefined, args: [] }`)
`profile.minecraft.version`	`string`	Minecraft version (e.g., `'1.20.1'`). Supports `'latest_release'` or `'latest_snapshot'`. Attention! Setting this forces the launcher to ignore the `url` property.	No
`profile.minecraft.loader`	`object`	Mod loader config for this specific profile. Ignored if `profile.minecraft.version` is not set.	No defaults to `vanilla`)
`profile.minecraft.loader.loader`	`'vanilla' \\| 'forge' \\| 'neoforge' \\| 'fabric' \\| 'quilt'`	The type of mod loader to utilize.	No defaults to `'vanilla'`)
`profile.minecraft.loader.version`	`string`	Specific version of the loader. Required for any loader other than `'vanilla'`.	No
`profile.minecraft.modpackUrl`	`string`	Direct URL to a modpack manifest (`.json`). Ignored if `profile.minecraft.version` is not set.	No
`profile.minecraft.args`	`string[]`	Custom Minecraft launch arguments for this profile. Use only if you know what you are doing!	No defaults to `[]`)
`storage`	`'isolated' \\| 'shared'`	Organization of game files: - `'isolated'`: Separate folder for each profile. - `'shared'`: Profiles share assets/libraries but separate `mods`, `config`, and `saves`. Attention! If `'shared'`, disable `cleaning.enabled`.	No defaults to `'isolated'`)
`root`	`string`	The name of the root game directory (e.g., `'minecraft'`). Automatically prefixed with a dot on Windows.	Yes
`minecraft`	`object`	Global Minecraft configuration. Attention! Overridden if `profile.minecraft` is defined with a valid version.	No
`minecraft.version`	`string`	Global Minecraft version. Supports `'latest_release'`/`'latest_snapshot'`. Attention! Setting this forces the launcher to ignore the `url` property.	No
`minecraft.loader`	`object`	Global mod loader configuration. Ignored if `minecraft.version` is not set.	No defaults to `vanilla`)
`minecraft.loader.loader`	`'vanilla' \\| 'forge' \\| 'neoforge' \\| 'fabric' \\| 'quilt'`	The type of mod loader to utilize globally.	No defaults to `'vanilla'`)
`minecraft.loader.version`	`string`	Specific version of the loader. Required for any loader other than `'vanilla'`.	No
`minecraft.modpackUrl`	`string`	Global modpack manifest URL (`.json`). Ignored if `minecraft.version` is not set.	No
`minecraft.args`	`string[]`	Global custom launch arguments. Use only if you know what you are doing!	No defaults to `[]`)
`cleaning.enabled`	`boolean`	Whether to remove unrecognized files from the instance folder. Attention! Must be `false` when `storage` is `'shared'`.	No defaults to `true`)
`cleaning.ignored`	`string[]`	Relative paths/files protected from cleaning (e.g., `saves/`, `options.txt`).	No defaults to standard Minecraft ignore list)
`account`	`Account`	Authenticated player account. Use `MicrosoftAuth`, `AzAuth`, `YggdrasilAuth`, or `CrackAuth`.	Yes
`java.install`	`'auto' \\| 'manual'`	- `'auto'`: Manages Java version automatically. - `'manual'`: Uses a pre-installed Java executable.	No defaults to `'auto'`)
`java.absolutePath`	`string`	Absolute path to Java. Required if `install` is `'manual'` and `relativePath` is missing. Attention! Overrides `java.relativePath`.	No
`java.relativePath`	`string`	Path relative to game `root` or `root/slug`. Ignored if `install` is `'auto'` or `absolutePath` is set.	No defaults to `runtime/jre-X/...`)
`java.args`	`string[]`	Custom JVM arguments. Attention! Do not use for Log4j; patches are applied automatically.	No defaults to `[]`)
`window`	`object`	Minecraft game window configuration (width, height, fullscreen).	No defaults to `854x480`)
`memory.min`	`number`	Minimum RAM allocated to Minecraft in MB.	No defaults to `512`)
`memory.max`	`number`	Maximum RAM allocated to Minecraft in MB.	No defaults to `1023`)

Events

Event	Description	Data
`launch_compute_download`	[STEP] The launcher is computing the download size of the files to download.	-
`launch_download`	[STEP] The launcher is downloading the files.	Total amount and size of the files to download.
`launch_install_loader`	[STEP] The launcher is installing the loader.	The loader information.
`launch_copy_assets`	[STEP] The launcher is copying the assets.	-
`launch_extract_natives`	[STEP] The launcher is extracting the natives.	-
`launch_patch_loader`	[STEP] The launcher is patching the loader.	-
`launch_check_java`	[STEP] The launcher is checking Java.	-
`launch_clean`	[STEP] The launcher is cleaning the game folder.	-
`launch_launch`	[STEP] The launcher is launching Minecraft.	Minecraft information (version, loader, loader version).
`launch_data`	[EVENT] Logs from Minecraft.	`string`
`launch_close`	[EVENT] Minecraft is closed.	`number` (code)
`launch_debug`	[EVENT] Debug logs from the launcher.	`string`
`download_progress`	[EVENT] The launcher is downloading a file.	The type of file being downloaded, the total amount and size of the files to download, the total amount and size of the downloaded files, the download speed.
`download_error`	[EVENT] An error occurred while downloading a file.	The filename and the type of file, and the error message.
`download_end`	[EVENT] The launcher has finished downloading a type of files.	The amount and size of the downladed files.
`extract_progress`	[EVENT] The launcher is extracting a file.	The filename.
`extract_end`	[EVENT] The launcher has finished extracting a type of files.	The amount of files extracted.
`copy_progress`	[EVENT] The launcher is copying a file.	The filename and its destination.
`copy_end`	[EVENT] The launcher has finished copying a type of files.	The amount of files copied.
`copy_debug`	[EVENT] Debug logs from the copying process.	`string`
`java_info`	[EVENT] Java information.	The Java version and architecture.
`patch_progress`	[EVENT] The launcher is patching a file.	The filename.
`patch_end`	[EVENT] The launcher has finished patching a type of files.	The amount of files patched.
`patch_error`	[EVENT] An error occurred while patching a file.	The filename and the error message.
`patch_debug`	[EVENT] Debug logs from the patching process.	`string`
`clean_progress`	[EVENT] The launcher is cleaning a file.	The filename.
`clean_end`	[EVENT] The launcher has finished cleaning a type of files.	The amount of files cleaned.

[STEP] - The event is a main step of the launch process.
[EVENT] - The event is an event of the step during the launch process.

Java

import { Java } from 'eml-lib'

async function java() {
  const java = new Java({
    url: 'https://at.emlproject.com',
    root: 'eml',
    minecraft: {
      version: '1.20.1'
    }
  })

  try {
    await java.download()
  } catch (err) {
    console.error(err)
  }
}

`Java` constructor

Field	Type	Description	Required?
`config.url`	`string`	The URL of your EML AdminTool website, where is stored your modpack and loader info.	No but strongly recommended
`config.root`	`string`	The name of the game folder, without the dot (e.g. `'minecraft'`). This will be used to create the server folder (e.g. `.minecraft`).	Yes
`config.minecraft.version`	`string`	The version of Minecraft you want to install Java for. Set to `'latest_release'` to install Java for the latest release version of Minecraft, or `'latest_snapshot'` to install Java for the latest snapshot. Set to `undefined` to get the version from the EML AdminTool.	No (defaults to `undefined`)

`Java.getFiles()` method

Get the files of the Java version to download.

Parameter	Type	Description	Required?
`manifest`	`MinecraftManifest`	The manifest of the Minecraft version. If not provided, the manifest will be fetched.	No

Returns: Promise<File[]> - The files of the Java version.

Throws: FETCH_ERROR - If a request to get data fails.

`Java.download()` method

Download Java for the Minecraft version.

Returns: Promise<void>

Throws: DOWNLOAD_ERROR - If an error occurs while downloading Java.

Emits: download_progress - The files are downloading. • download_error - Error while downloading the files. • download_end - The files are downloaded.

`Java.check()` method

Check if Java is correctly installed.

Parameter	Type	Description	Required?
`absolutePath`	`string`	Absolute path to the Java executable. You can use `${X}` to replace it with the major version of Java.	No (defaults to the installed Java path)
`majorVersion`	`number`	Major version of Java to check.	No (defaults to `8`)

Returns: Promise<{ version: string; arch: '64-bit' | '32-bit' }> - The version and architecture of Java.

Throws: JAVA_ERROR - If Java is not correctly installed or does not match the required major version.

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Launch settings

Launcher

Launcher constructor

Launcher.launch() method

Config object

Events

Java

Java constructor

Java.getFiles() method

Java.download() method

Java.check() method