如何避免事件监听器共享 Scope

Question

I'm making a bot for a game to move to a block and mine it by listening for events and I noticed something weird when trying to run async functions in a event listener. When the aysnc function finishes it runs a call back function using a variable that is declared in the second event listener called pos but once the function is called the event has already happened again. The call back function uses the new value from the event from the first listener instead of the old value from when the async function was called in the second listener. I was wondering how I could avoid this problem.

This the first event listener:

bot.client.on('block_change', packet => {
    let id = packet.type
    let loc = packet.location;
    let pos = new Vec3(Math.floor(loc.x), Math.floor(loc.y), Math.floor(loc.z))
    let block = new Block(Math.floor(id / 16), 5, id % 16)
    setBlock(pos, block);
});

This the second listener:

bot.client.on('block_change', (packet) => {
    loc = packet.location
    block = new Block(Math.floor(packet.type/16),0,packet.type%16)
    pos = new Vec3(loc.x,loc.y,loc.z)
    if (packet.type === 16) {
        bot.navigate.to(pos,{endRadius:3, onArrived: ()=>{bot.dig(pos)}});
    }
});

Answer 1

both listeners need to use the keyword "let" or "const" to change the global variables eg

bot.client.on('block_change', (packet) => {
    let loc = packet.location
    let block = new Block(Math.floor(packet.type/16),0,packet.type%16)
    let pos = new Vec3(loc.x,loc.y,loc.z)
    if (packet.type === 16) {
        bot.navigate.to(pos,{endRadius:3, onArrived: ()=>{bot.dig(pos)}});
    }
});