initial commit

app/assets/js/configmanager.js

@@ -0,0 +1,793 @@
+const fs   = require('fs-extra')
+const { LoggerUtil } = require('helios-core')
+const os   = require('os')
+const path = require('path')
+
+const logger = LoggerUtil.getLogger('ConfigManager')
+
+const sysRoot = process.env.APPDATA || (process.platform == 'darwin' ? process.env.HOME + '/Library/Application Support' : process.env.HOME)
+
+const dataPath = path.join(sysRoot, '.chencolauncher')
+
+const launcherDir = require('@electron/remote').app.getPath('userData')
+
+/**
+ * Retrieve the absolute path of the launcher directory.
+ * 
+ * @returns {string} The absolute path of the launcher directory.
+ */
+exports.getLauncherDirectory = function(){
+    return launcherDir
+}
+
+/**
+ * Get the launcher's data directory. This is where all files related
+ * to game launch are installed (common, instances, java, etc).
+ * 
+ * @returns {string} The absolute path of the launcher's data directory.
+ */
+exports.getDataDirectory = function(def = false){
+    return !def ? config.settings.launcher.dataDirectory : DEFAULT_CONFIG.settings.launcher.dataDirectory
+}
+
+/**
+ * Set the new data directory.
+ * 
+ * @param {string} dataDirectory The new data directory.
+ */
+exports.setDataDirectory = function(dataDirectory){
+    config.settings.launcher.dataDirectory = dataDirectory
+}
+
+const configPath = path.join(exports.getLauncherDirectory(), 'config.json')
+const configPathLEGACY = path.join(dataPath, 'config.json')
+const firstLaunch = !fs.existsSync(configPath) && !fs.existsSync(configPathLEGACY)
+
+exports.getAbsoluteMinRAM = function(ram){
+    if(ram?.minimum != null) {
+        return ram.minimum/1024
+    } else {
+        // Legacy behavior
+        const mem = os.totalmem()
+        return mem >= (6*1073741824) ? 3 : 2
+    }
+}
+
+exports.getAbsoluteMaxRAM = function(ram){
+    const mem = os.totalmem()
+    const gT16 = mem-(16*1073741824)
+    return Math.floor((mem-(gT16 > 0 ? (Number.parseInt(gT16/8) + (16*1073741824)/4) : mem/4))/1073741824)
+}
+
+function resolveSelectedRAM(ram) {
+    if(ram?.recommended != null) {
+        return `${ram.recommended}M`
+    } else {
+        // Legacy behavior
+        const mem = os.totalmem()
+        return mem >= (8*1073741824) ? '4G' : (mem >= (6*1073741824) ? '3G' : '2G')
+    }
+}
+
+/**
+ * Three types of values:
+ * Static = Explicitly declared.
+ * Dynamic = Calculated by a private function.
+ * Resolved = Resolved externally, defaults to null.
+ */
+const DEFAULT_CONFIG = {
+    settings: {
+        game: {
+            resWidth: 1280,
+            resHeight: 720,
+            fullscreen: false,
+            autoConnect: true,
+            launchDetached: true
+        },
+        launcher: {
+            allowPrerelease: false,
+            dataDirectory: dataPath
+        }
+    },
+    newsCache: {
+        date: null,
+        content: null,
+        dismissed: false
+    },
+    clientToken: null,
+    selectedServer: null, // Resolved
+    selectedAccount: null,
+    authenticationDatabase: {},
+    modConfigurations: [],
+    javaConfig: {}
+}
+
+let config = null
+
+// Persistance Utility Functions
+
+/**
+ * Save the current configuration to a file.
+ */
+exports.save = function(){
+    fs.writeFileSync(configPath, JSON.stringify(config, null, 4), 'UTF-8')
+}
+
+/**
+ * Load the configuration into memory. If a configuration file exists,
+ * that will be read and saved. Otherwise, a default configuration will
+ * be generated. Note that "resolved" values default to null and will
+ * need to be externally assigned.
+ */
+exports.load = function(){
+    let doLoad = true
+
+    if(!fs.existsSync(configPath)){
+        // Create all parent directories.
+        fs.ensureDirSync(path.join(configPath, '..'))
+        if(fs.existsSync(configPathLEGACY)){
+            fs.moveSync(configPathLEGACY, configPath)
+        } else {
+            doLoad = false
+            config = DEFAULT_CONFIG
+            exports.save()
+        }
+    }
+    if(doLoad){
+        let doValidate = false
+        try {
+            config = JSON.parse(fs.readFileSync(configPath, 'UTF-8'))
+            doValidate = true
+        } catch (err){
+            logger.error(err)
+            logger.info('Configuration file contains malformed JSON or is corrupt.')
+            logger.info('Generating a new configuration file.')
+            fs.ensureDirSync(path.join(configPath, '..'))
+            config = DEFAULT_CONFIG
+            exports.save()
+        }
+        if(doValidate){
+            config = validateKeySet(DEFAULT_CONFIG, config)
+            exports.save()
+        }
+    }
+    logger.info('Successfully Loaded')
+}
+
+/**
+ * @returns {boolean} Whether or not the manager has been loaded.
+ */
+exports.isLoaded = function(){
+    return config != null
+}
+
+/**
+ * Validate that the destination object has at least every field
+ * present in the source object. Assign a default value otherwise.
+ * 
+ * @param {Object} srcObj The source object to reference against.
+ * @param {Object} destObj The destination object.
+ * @returns {Object} A validated destination object.
+ */
+function validateKeySet(srcObj, destObj){
+    if(srcObj == null){
+        srcObj = {}
+    }
+    const validationBlacklist = ['authenticationDatabase', 'javaConfig']
+    const keys = Object.keys(srcObj)
+    for(let i=0; i<keys.length; i++){
+        if(typeof destObj[keys[i]] === 'undefined'){
+            destObj[keys[i]] = srcObj[keys[i]]
+        } else if(typeof srcObj[keys[i]] === 'object' && srcObj[keys[i]] != null && !(srcObj[keys[i]] instanceof Array) && validationBlacklist.indexOf(keys[i]) === -1){
+            destObj[keys[i]] = validateKeySet(srcObj[keys[i]], destObj[keys[i]])
+        }
+    }
+    return destObj
+}
+
+/**
+ * Check to see if this is the first time the user has launched the
+ * application. This is determined by the existance of the data path.
+ * 
+ * @returns {boolean} True if this is the first launch, otherwise false.
+ */
+exports.isFirstLaunch = function(){
+    return firstLaunch
+}
+
+/**
+ * Returns the name of the folder in the OS temp directory which we
+ * will use to extract and store native dependencies for game launch.
+ * 
+ * @returns {string} The name of the folder.
+ */
+exports.getTempNativeFolder = function(){
+    return 'WCNatives'
+}
+
+// System Settings (Unconfigurable on UI)
+
+/**
+ * Retrieve the news cache to determine
+ * whether or not there is newer news.
+ * 
+ * @returns {Object} The news cache object.
+ */
+exports.getNewsCache = function(){
+    return config.newsCache
+}
+
+/**
+ * Set the new news cache object.
+ * 
+ * @param {Object} newsCache The new news cache object.
+ */
+exports.setNewsCache = function(newsCache){
+    config.newsCache = newsCache
+}
+
+/**
+ * Set whether or not the news has been dismissed (checked)
+ * 
+ * @param {boolean} dismissed Whether or not the news has been dismissed (checked).
+ */
+exports.setNewsCacheDismissed = function(dismissed){
+    config.newsCache.dismissed = dismissed
+}
+
+/**
+ * Retrieve the common directory for shared
+ * game files (assets, libraries, etc).
+ * 
+ * @returns {string} The launcher's common directory.
+ */
+exports.getCommonDirectory = function(){
+    return path.join(exports.getDataDirectory(), 'common')
+}
+
+/**
+ * Retrieve the instance directory for the per
+ * server game directories.
+ * 
+ * @returns {string} The launcher's instance directory.
+ */
+exports.getInstanceDirectory = function(){
+    return path.join(exports.getDataDirectory(), 'instances')
+}
+
+/**
+ * Retrieve the launcher's Client Token.
+ * There is no default client token.
+ * 
+ * @returns {string} The launcher's Client Token.
+ */
+exports.getClientToken = function(){
+    return config.clientToken
+}
+
+/**
+ * Set the launcher's Client Token.
+ * 
+ * @param {string} clientToken The launcher's new Client Token.
+ */
+exports.setClientToken = function(clientToken){
+    config.clientToken = clientToken
+}
+
+/**
+ * Retrieve the ID of the selected serverpack.
+ * 
+ * @param {boolean} def Optional. If true, the default value will be returned.
+ * @returns {string} The ID of the selected serverpack.
+ */
+exports.getSelectedServer = function(def = false){
+    return !def ? config.selectedServer : DEFAULT_CONFIG.clientToken
+}
+
+/**
+ * Set the ID of the selected serverpack.
+ * 
+ * @param {string} serverID The ID of the new selected serverpack.
+ */
+exports.setSelectedServer = function(serverID){
+    config.selectedServer = serverID
+}
+
+/**
+ * Get an array of each account currently authenticated by the launcher.
+ * 
+ * @returns {Array.<Object>} An array of each stored authenticated account.
+ */
+exports.getAuthAccounts = function(){
+    return config.authenticationDatabase
+}
+
+/**
+ * Returns the authenticated account with the given uuid. Value may
+ * be null.
+ * 
+ * @param {string} uuid The uuid of the authenticated account.
+ * @returns {Object} The authenticated account with the given uuid.
+ */
+exports.getAuthAccount = function(uuid){
+    return config.authenticationDatabase[uuid]
+}
+
+/**
+ * Update the access token of an authenticated mojang account.
+ * 
+ * @param {string} uuid The uuid of the authenticated account.
+ * @param {string} accessToken The new Access Token.
+ * 
+ * @returns {Object} The authenticated account object created by this action.
+ */
+exports.updateMojangAuthAccount = function(uuid, accessToken){
+    config.authenticationDatabase[uuid].accessToken = accessToken
+    config.authenticationDatabase[uuid].type = 'mojang' // For gradual conversion.
+    return config.authenticationDatabase[uuid]
+}
+
+/**
+ * Adds an authenticated mojang account to the database to be stored.
+ * 
+ * @param {string} uuid The uuid of the authenticated account.
+ * @param {string} accessToken The accessToken of the authenticated account.
+ * @param {string} username The username (usually email) of the authenticated account.
+ * @param {string} displayName The in game name of the authenticated account.
+ * 
+ * @returns {Object} The authenticated account object created by this action.
+ */
+exports.addMojangAuthAccount = function(uuid, accessToken, username, displayName){
+    config.selectedAccount = uuid
+    config.authenticationDatabase[uuid] = {
+        type: 'mojang',
+        accessToken,
+        username: username.trim(),
+        uuid: uuid.trim(),
+        displayName: displayName.trim()
+    }
+    return config.authenticationDatabase[uuid]
+}
+
+/**
+ * Update the tokens of an authenticated microsoft account.
+ * 
+ * @param {string} uuid The uuid of the authenticated account.
+ * @param {string} accessToken The new Access Token.
+ * @param {string} msAccessToken The new Microsoft Access Token
+ * @param {string} msRefreshToken The new Microsoft Refresh Token
+ * @param {date} msExpires The date when the microsoft access token expires
+ * @param {date} mcExpires The date when the mojang access token expires
+ * 
+ * @returns {Object} The authenticated account object created by this action.
+ */
+exports.updateMicrosoftAuthAccount = function(uuid, accessToken, msAccessToken, msRefreshToken, msExpires, mcExpires) {
+    config.authenticationDatabase[uuid].accessToken = accessToken
+    config.authenticationDatabase[uuid].expiresAt = mcExpires
+    config.authenticationDatabase[uuid].microsoft.access_token = msAccessToken
+    config.authenticationDatabase[uuid].microsoft.refresh_token = msRefreshToken
+    config.authenticationDatabase[uuid].microsoft.expires_at = msExpires
+    return config.authenticationDatabase[uuid]
+}
+
+/**
+ * Adds an authenticated microsoft account to the database to be stored.
+ * 
+ * @param {string} uuid The uuid of the authenticated account.
+ * @param {string} accessToken The accessToken of the authenticated account.
+ * @param {string} name The in game name of the authenticated account.
+ * @param {date} mcExpires The date when the mojang access token expires
+ * @param {string} msAccessToken The microsoft access token
+ * @param {string} msRefreshToken The microsoft refresh token
+ * @param {date} msExpires The date when the microsoft access token expires
+ * 
+ * @returns {Object} The authenticated account object created by this action.
+ */
+exports.addMicrosoftAuthAccount = function(uuid, accessToken, name, mcExpires, msAccessToken, msRefreshToken, msExpires) {
+    config.selectedAccount = uuid
+    config.authenticationDatabase[uuid] = {
+        type: 'microsoft',
+        accessToken,
+        username: name.trim(),
+        uuid: uuid.trim(),
+        displayName: name.trim(),
+        expiresAt: mcExpires,
+        microsoft: {
+            access_token: msAccessToken,
+            refresh_token: msRefreshToken,
+            expires_at: msExpires
+        }
+    }
+    return config.authenticationDatabase[uuid]
+}
+
+/**
+ * Remove an authenticated account from the database. If the account
+ * was also the selected account, a new one will be selected. If there
+ * are no accounts, the selected account will be null.
+ * 
+ * @param {string} uuid The uuid of the authenticated account.
+ * 
+ * @returns {boolean} True if the account was removed, false if it never existed.
+ */
+exports.removeAuthAccount = function(uuid){
+    if(config.authenticationDatabase[uuid] != null){
+        delete config.authenticationDatabase[uuid]
+        if(config.selectedAccount === uuid){
+            const keys = Object.keys(config.authenticationDatabase)
+            if(keys.length > 0){
+                config.selectedAccount = keys[0]
+            } else {
+                config.selectedAccount = null
+                config.clientToken = null
+            }
+        }
+        return true
+    }
+    return false
+}
+
+/**
+ * Get the currently selected authenticated account.
+ * 
+ * @returns {Object} The selected authenticated account.
+ */
+exports.getSelectedAccount = function(){
+    return config.authenticationDatabase[config.selectedAccount]
+}
+
+/**
+ * Set the selected authenticated account.
+ * 
+ * @param {string} uuid The UUID of the account which is to be set
+ * as the selected account.
+ * 
+ * @returns {Object} The selected authenticated account.
+ */
+exports.setSelectedAccount = function(uuid){
+    const authAcc = config.authenticationDatabase[uuid]
+    if(authAcc != null) {
+        config.selectedAccount = uuid
+    }
+    return authAcc
+}
+
+/**
+ * Get an array of each mod configuration currently stored.
+ * 
+ * @returns {Array.<Object>} An array of each stored mod configuration.
+ */
+exports.getModConfigurations = function(){
+    return config.modConfigurations
+}
+
+/**
+ * Set the array of stored mod configurations.
+ * 
+ * @param {Array.<Object>} configurations An array of mod configurations.
+ */
+exports.setModConfigurations = function(configurations){
+    config.modConfigurations = configurations
+}
+
+/**
+ * Get the mod configuration for a specific server.
+ * 
+ * @param {string} serverid The id of the server.
+ * @returns {Object} The mod configuration for the given server.
+ */
+exports.getModConfiguration = function(serverid){
+    const cfgs = config.modConfigurations
+    for(let i=0; i<cfgs.length; i++){
+        if(cfgs[i].id === serverid){
+            return cfgs[i]
+        }
+    }
+    return null
+}
+
+/**
+ * Set the mod configuration for a specific server. This overrides any existing value.
+ * 
+ * @param {string} serverid The id of the server for the given mod configuration.
+ * @param {Object} configuration The mod configuration for the given server.
+ */
+exports.setModConfiguration = function(serverid, configuration){
+    const cfgs = config.modConfigurations
+    for(let i=0; i<cfgs.length; i++){
+        if(cfgs[i].id === serverid){
+            cfgs[i] = configuration
+            return
+        }
+    }
+    cfgs.push(configuration)
+}
+
+// User Configurable Settings
+
+// Java Settings
+
+function defaultJavaConfig(effectiveJavaOptions, ram) {
+    if(effectiveJavaOptions.suggestedMajor > 8) {
+        return defaultJavaConfig17(ram)
+    } else {
+        return defaultJavaConfig8(ram)
+    }
+}
+
+function defaultJavaConfig8(ram) {
+    return {
+        minRAM: resolveSelectedRAM(ram),
+        maxRAM: resolveSelectedRAM(ram),
+        executable: null,
+        jvmOptions: [
+            '-XX:+UseConcMarkSweepGC',
+            '-XX:+CMSIncrementalMode',
+            '-XX:-UseAdaptiveSizePolicy',
+            '-Xmn128M'
+        ],
+    }
+}
+
+function defaultJavaConfig17(ram) {
+    return {
+        minRAM: resolveSelectedRAM(ram),
+        maxRAM: resolveSelectedRAM(ram),
+        executable: null,
+        jvmOptions: [
+            '-XX:+UnlockExperimentalVMOptions',
+            '-XX:+UseG1GC',
+            '-XX:G1NewSizePercent=20',
+            '-XX:G1ReservePercent=20',
+            '-XX:MaxGCPauseMillis=50',
+            '-XX:G1HeapRegionSize=32M'
+        ],
+    }
+}
+
+/**
+ * Ensure a java config property is set for the given server.
+ * 
+ * @param {string} serverid The server id.
+ * @param {*} mcVersion The minecraft version of the server.
+ */
+exports.ensureJavaConfig = function(serverid, effectiveJavaOptions, ram) {
+    if(!Object.prototype.hasOwnProperty.call(config.javaConfig, serverid)) {
+        config.javaConfig[serverid] = defaultJavaConfig(effectiveJavaOptions, ram)
+    }
+}
+
+/**
+ * Retrieve the minimum amount of memory for JVM initialization. This value
+ * contains the units of memory. For example, '5G' = 5 GigaBytes, '1024M' = 
+ * 1024 MegaBytes, etc.
+ * 
+ * @param {string} serverid The server id.
+ * @returns {string} The minimum amount of memory for JVM initialization.
+ */
+exports.getMinRAM = function(serverid){
+    return config.javaConfig[serverid].minRAM
+}
+
+/**
+ * Set the minimum amount of memory for JVM initialization. This value should
+ * contain the units of memory. For example, '5G' = 5 GigaBytes, '1024M' = 
+ * 1024 MegaBytes, etc.
+ * 
+ * @param {string} serverid The server id.
+ * @param {string} minRAM The new minimum amount of memory for JVM initialization.
+ */
+exports.setMinRAM = function(serverid, minRAM){
+    config.javaConfig[serverid].minRAM = minRAM
+}
+
+/**
+ * Retrieve the maximum amount of memory for JVM initialization. This value
+ * contains the units of memory. For example, '5G' = 5 GigaBytes, '1024M' = 
+ * 1024 MegaBytes, etc.
+ * 
+ * @param {string} serverid The server id.
+ * @returns {string} The maximum amount of memory for JVM initialization.
+ */
+exports.getMaxRAM = function(serverid){
+    return config.javaConfig[serverid].maxRAM
+}
+
+/**
+ * Set the maximum amount of memory for JVM initialization. This value should
+ * contain the units of memory. For example, '5G' = 5 GigaBytes, '1024M' = 
+ * 1024 MegaBytes, etc.
+ * 
+ * @param {string} serverid The server id.
+ * @param {string} maxRAM The new maximum amount of memory for JVM initialization.
+ */
+exports.setMaxRAM = function(serverid, maxRAM){
+    config.javaConfig[serverid].maxRAM = maxRAM
+}
+
+/**
+ * Retrieve the path of the Java Executable.
+ * 
+ * This is a resolved configuration value and defaults to null until externally assigned.
+ * 
+ * @param {string} serverid The server id.
+ * @returns {string} The path of the Java Executable.
+ */
+exports.getJavaExecutable = function(serverid){
+    return config.javaConfig[serverid].executable
+}
+
+/**
+ * Set the path of the Java Executable.
+ * 
+ * @param {string} serverid The server id.
+ * @param {string} executable The new path of the Java Executable.
+ */
+exports.setJavaExecutable = function(serverid, executable){
+    config.javaConfig[serverid].executable = executable
+}
+
+/**
+ * Retrieve the additional arguments for JVM initialization. Required arguments,
+ * such as memory allocation, will be dynamically resolved and will not be included
+ * in this value.
+ * 
+ * @param {string} serverid The server id.
+ * @returns {Array.<string>} An array of the additional arguments for JVM initialization.
+ */
+exports.getJVMOptions = function(serverid){
+    return config.javaConfig[serverid].jvmOptions
+}
+
+/**
+ * Set the additional arguments for JVM initialization. Required arguments,
+ * such as memory allocation, will be dynamically resolved and should not be
+ * included in this value.
+ * 
+ * @param {string} serverid The server id.
+ * @param {Array.<string>} jvmOptions An array of the new additional arguments for JVM 
+ * initialization.
+ */
+exports.setJVMOptions = function(serverid, jvmOptions){
+    config.javaConfig[serverid].jvmOptions = jvmOptions
+}
+
+// Game Settings
+
+/**
+ * Retrieve the width of the game window.
+ * 
+ * @param {boolean} def Optional. If true, the default value will be returned.
+ * @returns {number} The width of the game window.
+ */
+exports.getGameWidth = function(def = false){
+    return !def ? config.settings.game.resWidth : DEFAULT_CONFIG.settings.game.resWidth
+}
+
+/**
+ * Set the width of the game window.
+ * 
+ * @param {number} resWidth The new width of the game window.
+ */
+exports.setGameWidth = function(resWidth){
+    config.settings.game.resWidth = Number.parseInt(resWidth)
+}
+
+/**
+ * Validate a potential new width value.
+ * 
+ * @param {number} resWidth The width value to validate.
+ * @returns {boolean} Whether or not the value is valid.
+ */
+exports.validateGameWidth = function(resWidth){
+    const nVal = Number.parseInt(resWidth)
+    return Number.isInteger(nVal) && nVal >= 0
+}
+
+/**
+ * Retrieve the height of the game window.
+ * 
+ * @param {boolean} def Optional. If true, the default value will be returned.
+ * @returns {number} The height of the game window.
+ */
+exports.getGameHeight = function(def = false){
+    return !def ? config.settings.game.resHeight : DEFAULT_CONFIG.settings.game.resHeight
+}
+
+/**
+ * Set the height of the game window.
+ * 
+ * @param {number} resHeight The new height of the game window.
+ */
+exports.setGameHeight = function(resHeight){
+    config.settings.game.resHeight = Number.parseInt(resHeight)
+}
+
+/**
+ * Validate a potential new height value.
+ * 
+ * @param {number} resHeight The height value to validate.
+ * @returns {boolean} Whether or not the value is valid.
+ */
+exports.validateGameHeight = function(resHeight){
+    const nVal = Number.parseInt(resHeight)
+    return Number.isInteger(nVal) && nVal >= 0
+}
+
+/**
+ * Check if the game should be launched in fullscreen mode.
+ * 
+ * @param {boolean} def Optional. If true, the default value will be returned.
+ * @returns {boolean} Whether or not the game is set to launch in fullscreen mode.
+ */
+exports.getFullscreen = function(def = false){
+    return !def ? config.settings.game.fullscreen : DEFAULT_CONFIG.settings.game.fullscreen
+}
+
+/**
+ * Change the status of if the game should be launched in fullscreen mode.
+ * 
+ * @param {boolean} fullscreen Whether or not the game should launch in fullscreen mode.
+ */
+exports.setFullscreen = function(fullscreen){
+    config.settings.game.fullscreen = fullscreen
+}
+
+/**
+ * Check if the game should auto connect to servers.
+ * 
+ * @param {boolean} def Optional. If true, the default value will be returned.
+ * @returns {boolean} Whether or not the game should auto connect to servers.
+ */
+exports.getAutoConnect = function(def = false){
+    return !def ? config.settings.game.autoConnect : DEFAULT_CONFIG.settings.game.autoConnect
+}
+
+/**
+ * Change the status of whether or not the game should auto connect to servers.
+ * 
+ * @param {boolean} autoConnect Whether or not the game should auto connect to servers.
+ */
+exports.setAutoConnect = function(autoConnect){
+    config.settings.game.autoConnect = autoConnect
+}
+
+/**
+ * Check if the game should launch as a detached process.
+ * 
+ * @param {boolean} def Optional. If true, the default value will be returned.
+ * @returns {boolean} Whether or not the game will launch as a detached process.
+ */
+exports.getLaunchDetached = function(def = false){
+    return !def ? config.settings.game.launchDetached : DEFAULT_CONFIG.settings.game.launchDetached
+}
+
+/**
+ * Change the status of whether or not the game should launch as a detached process.
+ * 
+ * @param {boolean} launchDetached Whether or not the game should launch as a detached process.
+ */
+exports.setLaunchDetached = function(launchDetached){
+    config.settings.game.launchDetached = launchDetached
+}
+
+// Launcher Settings
+
+/**
+ * Check if the launcher should download prerelease versions.
+ * 
+ * @param {boolean} def Optional. If true, the default value will be returned.
+ * @returns {boolean} Whether or not the launcher should download prerelease versions.
+ */
+exports.getAllowPrerelease = function(def = false){
+    return !def ? config.settings.launcher.allowPrerelease : DEFAULT_CONFIG.settings.launcher.allowPrerelease
+}
+
+/**
+ * Change the status of Whether or not the launcher should download prerelease versions.
+ * 
+ * @param {boolean} launchDetached Whether or not the launcher should download prerelease versions.
+ */
+exports.setAllowPrerelease = function(allowPrerelease){
+    config.settings.launcher.allowPrerelease = allowPrerelease
+}