Example addon for ModPE.

// IN MAIN FILE
const ScriptableObject_ = org.mozilla.javascript.ScriptableObject;

var ScriptManager_ = com.mcbox.pesdk.mcpelauncher.ScriptManager;
var ScriptManager__ = net.zhuoweizhang.mcpelauncher.ScriptManager;
var ctx = com.mojang.minecraftpe.MainActivity.currentMainActivity.get();
var addons = [];

var Launcher = {
    isBlockLauncher: function() {
        return (ctx.getPackageName() == "net.zhuoweizhang.mcpelauncher" || ctx.getPackageName() == "net.zhuoweizhang.mcpelauncher.pro");
    },
    isToolbox: function() {
        return ctx.getPackageName() == "io.mrarm.mctoolbox";
    },
    isMcpeMaster: function() {
        return ctx.getPackageName() == "com.mcbox.pesdkb.mcpelauncher";
    }
};

var mainScriptName = "IceAttack"; //example
(function loadAddons() {
    if(Launcher.isBlockLauncher() || Launcher.isToolbox()) {
        ScriptManager__.callScriptMethod("addonLoadHook", [mainScriptName]);
    }
    if(Launcher.isMcpeMaster()) {
        ScriptManager_.callScriptMethod("addonLoadHook", [mainScriptName]);
    }
})();

function registerAddon(name, desc, current_version, target_version, author) {
    var shouldMessage = true;
    try {
        let scripts;
        if(Launcher.isBlockLauncher() || Launcher.isToolbox()) {
            scripts = ScriptManager__.scripts;
        } else {
            scripts = ScriptManager_.scripts;
        }
        let scriptName;
        for(var i = 0; i < scripts.size(); i++) {
            var script = scripts.get(i);
            var scope = script.scope;
            if(ScriptableObject_.hasProperty(scope, "ADDON_NAME") && ScriptableObject_.hasProperty(scope, "ADDON_VERSION")) {
                if(ScriptableObject_.getProperty(scope, "ADDON_NAME") == name && ScriptableObject_.getProperty(scope, "ADDON_VERSION") == current_version) {
                    scriptName = script.name;
                    break;
                }
            }
        }
        addons.push({
            name: name,
            desc: desc,
            author: author==null?"Unknown":author,
            current_version: current_version,
            target_version: target_version,
            scriptName: scriptName
        });
    } catch(e) {
        shouldMessage = false;
        print("[" + mainScriptName + "] An error occurred while loading addons: " + e);
    }

    if(shouldMessage) {
        print("[" + mainScriptName + "] Successfully loaded the addon with name " + name + "!");
    }
}

/*

    Afterwards, the main script will have all the loaded addons stored in the addons array,
    which makes it possible to use a for loop on it. For example you can do addons[i].name
    which returns the name of the addon at index i in the addons array.

*/

// IN ADDON FILE

const ADDON_NAME = "BestAddon for IceAttack!";
const ADDON_DESC = "It's just the best.";
const ADDON_AUTHOR = "Smasher & peacestorm ;)."; //<< examples
const ADDON_VERSION = "1.0"
const TARGET_VERSION = "1.0"; //this means the addon is compatible with version 1.0 of the main script

var ScriptManager_ = com.mcbox.pesdk.mcpelauncher.ScriptManager;
var ScriptManager__ = net.zhuoweizhang.mcpelauncher.ScriptManager;
var ctx = com.mojang.minecraftpe.MainActivity.currentMainActivity.get();

var Launcher = {
    isBlockLauncher: function() {
        return (ctx.getPackageName() == "net.zhuoweizhang.mcpelauncher" || ctx.getPackageName() == "net.zhuoweizhang.mcpelauncher.pro");
    },
    isToolbox: function() {
        return ctx.getPackageName() == "io.mrarm.mctoolbox";
    },
    isMcpeMaster: function() {
        return ctx.getPackageName() == "com.mcbox.pesdkb.mcpelauncher";
    }
};

function addonLoadHook(mainScriptName) {
    if(mainScriptName == "IceAttack") { //insert main script name
        if(Launcher.isBlockLauncher() || Launcher.isToolbox()) {
            net.zhuoweizhang.mcpelauncher.ScriptManager.callScriptMethod("registerAddon", [ADDON_NAME, ADDON_DESC, ADDON_VERSION, TARGET_VERSION, ADDON_AUTHOR]);
        }
        if(Launcher.isMcpeMaster()) {
            com.mcbox.pesdk.mcpelauncher.ScriptManager.callScriptMethod("registerAddon", [ADDON_NAME, ADDON_DESC, ADDON_VERSION, TARGET_VERSION, ADDON_AUTHOR]);
        }
    }
}