Class PistonActivateBeforeEventSignalBeta

Remarks

Adds a callback that will be called before a piston expands or retracts.

This function can't be called in read-only mode.

Example

pistonBeforeEvent.ts

  // set up a couple of piston blocks
  let piston = overworld.getBlock(targetLocation);
  let button = overworld.getBlock({ x: targetLocation.x, y: targetLocation.y + 1, z: targetLocation.z });

  if (piston === undefined || button === undefined) {
    log("Could not find block at location.");
    return -1;
  }

  piston.setPermutation(mc.BlockPermutation.resolve('piston').withState('facing_direction', 3));
  button.setPermutation(mc.BlockPermutation.resolve('acacia_button').withState('facing_direction', 1));

  const uncanceledPistonLoc = {
    x: Math.floor(targetLocation.x) + 2,
    y: Math.floor(targetLocation.y),
    z: Math.floor(targetLocation.z) + 2,
  };

  // this is our control.
  let uncanceledPiston = overworld.getBlock(uncanceledPistonLoc);
  let uncanceledButton = overworld.getBlock({
    x: uncanceledPistonLoc.x,
    y: uncanceledPistonLoc.y + 1,
    z: uncanceledPistonLoc.z,
  });

  if (uncanceledPiston === undefined || uncanceledButton === undefined) {
    log("Could not find block at location.");
    return -1;
  }

  uncanceledPiston.setPermutation(mc.BlockPermutation.resolve('piston').withState('facing_direction', 3));
  uncanceledButton.setPermutation(mc.BlockPermutation.resolve('acacia_button').withState('facing_direction', 1));

  mc.world.beforeEvents.pistonActivate.subscribe((pistonEvent: mc.PistonActivateBeforeEvent) => {
    let eventLoc = pistonEvent.piston.block.location;
    if (eventLoc.x === targetLocation.x && eventLoc.y === targetLocation.y && eventLoc.z === targetLocation.z) {
      log("Cancelling piston event");
      pistonEvent.cancel = true;
    }
  });
Copy

Remarks

Removes a callback from being called before a piston expands or retracts.

This function can't be called in read-only mode.

Throws

This function can throw errors.