check if user reacted to a message discord.js code example

Example 1: see if discord message is in dm discord.js

if(message.channel.type === 'dm'){
	message.channel.send("Pog");
}

Example 2: how to test on user reaction discord.js

client.on('messageReactionAdd', (reaction, user) => {
    console.log('a reaction has been added');
});

Example 3: how to check if a user sent a message in discord js

if(message.author.id === client.user.id) return;