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System Class

A class that provides system-level events and functions.

Properties

afterEvents

read-only afterEvents: SystemAfterEvents;

Returns a collection of after-events for system-level operations.

Type: SystemAfterEvents

beforeEvents

read-only beforeEvents: SystemBeforeEvents;

Returns a collection of before-events for system-level operations.

Type: SystemBeforeEvents

Caution

This property is still in pre-release. Its signature may change or it may be removed in future releases.

currentTick

read-only currentTick: number;

Represents the current world tick of the server.

Type: number

serverSystemInfo

read-only serverSystemInfo: SystemInfo;

Contains the device information for the server.

Type: SystemInfo

Methods

clearJob

clearJob(jobId: number): void

Cancels the execution of a job queued via @minecraft/server.System.runJob.

Parameters

Notes:

clearRun

clearRun(runId: number): void

Cancels the execution of a function run that was previously scheduled via @minecraft/server.System.run.

Parameters

  • runId: number

Notes:

run

run(callback: () => void): number

Runs a specified function at the next available future time. This is frequently used to implement delayed behaviors and game loops. When run within the context of an event handler, this will generally run the code at the end of the same tick where the event occurred. When run in other code (a system.run callout), this will run the function in the next tick. Note, however, that depending on load on the system, running in the same or next tick is not guaranteed.

Parameters

  • callback: () => void

    Function callback to run at the next game tick.

Returns number - An opaque identifier that can be used with the clearRun function to cancel the execution of this run.

Notes:

Examples

trapTick.ts
import { world, system } from "@minecraft/server";

function trapTick() {
  try {
    // Minecraft runs at 20 ticks per second.
    if (system.currentTick % 1200 === 0) {
      world.sendMessage("Another minute passes...");
    }
  } catch (e) {
    console.warn("Error: " + e);
  }

  system.run(trapTick);
}

(preview) Work with this sample on the MCTools.dev code sandbox.

runInterval

runInterval(callback: () => void, tickInterval?: number): number

Runs a set of code on an interval.

Parameters

  • callback: () => void

    Functional code that will run when this interval occurs.

  • tickInterval?: number = null

    An interval of every N ticks that the callback will be called upon.

Returns number - An opaque handle that can be used with the clearRun method to stop the run of this function on an interval.

Notes:

Examples

every30Seconds.ts
import { world, system, DimensionLocation } from "@minecraft/server";

function every30Seconds(targetLocation: DimensionLocation) {
  const intervalRunIdentifier = Math.floor(Math.random() * 10000);

  system.runInterval(() => {
    world.sendMessage("This is an interval run " + intervalRunIdentifier + " sending a message every 30 seconds.");
  }, 600);
}

(preview) Work with this sample on the MCTools.dev code sandbox.

runJob

runJob(generator: Generator<void, void, void>): number

Queues a generator to run until completion. The generator will be given a time slice each tick, and will be run until it yields or completes.

Parameters

  • generator: Generator<void, void, void>

    The instance of the generator to run.

Returns number - An opaque handle that can be used with @minecraft/server.System.clearJob to stop the run of this generator.

Notes:

Examples

cubeGenerator.ts
import { system, BlockPermutation, DimensionLocation } from "@minecraft/server";

function cubeGenerator(targetLocation: DimensionLocation) {
  const blockPerm = BlockPermutation.resolve("minecraft:cobblestone");

  system.runJob(blockPlacingGenerator(blockPerm, targetLocation, 15));
}

function* blockPlacingGenerator(blockPerm: BlockPermutation, startingLocation: DimensionLocation, size: number) {
  for (let x = startingLocation.x; x < startingLocation.x + size; x++) {
    for (let y = startingLocation.y; y < startingLocation.y + size; y++) {
      for (let z = startingLocation.z; z < startingLocation.z + size; z++) {
        const block = startingLocation.dimension.getBlock({ x: x, y: y, z: z });
        if (block) {
          block.setPermutation(blockPerm);
        }
        yield;
      }
    }
  }
}

(preview) Work with this sample on the MCTools.dev code sandbox.

runTimeout

runTimeout(callback: () => void, tickDelay?: number): number

Runs a set of code at a future time specified by tickDelay.

Parameters

  • callback: () => void

    Functional code that will run when this timeout occurs.

  • tickDelay?: number = null

    Amount of time, in ticks, before the interval will be called.

Returns number - An opaque handle that can be used with the clearRun method to stop the run of this function on an interval.

Notes:

scriptEvent

scriptEvent(id: string, message: string): void

Causes an event to fire within script with the specified message ID and payload.

Parameters

  • id: string

    Identifier of the message to send. This is custom and dependent on the kinds of behavior packs and content you may have installed within the world.

  • message: string

    Data component of the message to send. This is custom and dependent on the kinds of behavior packs and content you may have installed within the world. Message may not exceed 2048 characters in length.

Caution

This function is still in pre-release. Its signature may change or it may be removed in future releases.

Notes:

waitTicks

waitTicks(ticks: number): Promise<void>

waitTicks returns a promise that resolves after the requested number of ticks.

Parameters

  • ticks: number

    The amount of ticks to wait. Minimum value is 1.

Returns Promise<void> - A promise that is resolved when the specified amount of ticks have occurred.

Notes: