flying-squid/src/lib/playerPlugins/chest.js

var vec3 = require("vec3");

module.exports=inject;

function inject(serv, player)
{
  player._client.on('block_place', async function (packet) {
    var referencePosition=new vec3(packet.location.x,packet.location.y,packet.location.z);
    if (player.entity.crouching) return;
    var id = await serv.world.getBlockType(referencePosition);
    var blockAbove = await serv.world.getBlockType(referencePosition.clone().add(new vec3(0, 1, 0)));

    if(id==54) {
      if (blockAbove) {
        return;
      }
      player._client.write("open_window",{
          windowId:165,
          inventoryType:"minecraft:chest",
          windowTitle:JSON.stringify("Chest"),
          slotCount:9*3 + 8 // 3 rows, make nicer later
      });
    }
    
  });
}