discord.js message delete(timeout code example
Example 1: discord js delete message after time
message.reply('Invalid command')
.then(msg => {
msg.delete({ timeout: 20000 /*time unitl delete in milliseconds*/});
})
.catch(/*Your Error handling if the Message isn't returned, sent, etc.*/);
Example 2: discord js delete message after time
message.channel.send("Hello World!").then(msg=>msg.delete({timeout:"2000"/*Time until delete in milliseconds*/})