Scheduler API

The Scheduler API lets you execute JS tasks with an active transaction (Tx) so you can safely use world and server, similar to Bukkit.

All callbacks run in a safe context without deadlocks.

⚠️ Do not use world or server.getPlayers() inside setInterval / setTimeout. Use scheduler instead.

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API

scheduler.run(fn)
scheduler.runLater(ticks, fn)
scheduler.runRepeating(ticks, fn) // returns task.cancel()

• ticks: one tick equals 50ms (20 ticks = 1s)
• fn: receives (world, server) as arguments

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Real-world examples

1) Run a task immediately

scheduler.run(function(world, server) {
    world.setBlock(0, 64, 0, "minecraft:diamond_block");
});

2) Run once after 2 seconds

scheduler.runLater(40, function(world, server) {
    server.broadcast("§aEvent started!");
});

3) Repeat every second

var task = scheduler.runRepeating(20, function(world, server) {
    server.broadcast("§7Players: §f" + server.getPlayerCount());
});

// stop later
// task.cancel();

4) Use world + player with scoreboard

scheduler.runRepeating(5, function(world, server) {
    var players = server.getPlayers();
    for (var i = 0; i < players.length; i++) {
        var p = players[i];
        var sb = scoreboard.create("§aServer");
        sb.setLines([
            "§7Coords: " + Math.floor(p.getX()) + " " + Math.floor(p.getY()) + " " + Math.floor(p.getZ()),
            "§7Block below: " + world.getBlock(Math.floor(p.getX()), Math.floor(p.getY()) - 1, Math.floor(p.getZ()))
        ]);
        p.sendScoreboard(sb);
    }
});

5) Access chest inventories

scheduler.run(function(world) {
    var inv = world.getInventory(0, 64, 0);
    if (inv) {
        inv.addItem("minecraft:diamond", 1);
    }
});

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Why use scheduler?

• world and server require an active Tx.
• setTimeout and setInterval have no Tx → can deadlock.
• Scheduler always runs inside World.Exec() with safe Tx.

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Cancellation

var task = scheduler.runRepeating(20, function(world, server) {
    server.broadcast("tick");
});

// cancel anytime
// task.cancel();