Why do both promise .then() and .catch() are called?

Question

I'm beginning to write a discord bot with the Discord.js library (version 11.5.1). Promises returned by methods don't work as expected because then() and catch() callbacks are both called if it's successful.

I'm using nodejs version 11.15.0.

In this example, I send a message in the test-bot channel when the bot in logged.

const Discord = require('discord.js');
const client = new Discord.Client();
const auth = require('./auth.json');

client.on('ready', () => {
    const guild = client.guilds.find(
        guild => guild.name === 'test');
    const channel = guild.channels.find(
        ch => ch.name === 'test-bot');
    if (!channel) {
        console.error('no channel found');
        return ;
    }
    channel.send('heeeello')
        .then(console.log('cool'))
        .catch(console.error('grrr'));
});
client.login(auth.token);

The message is well sended on the discord channel and the console output is:

cool
grrr

but I don't expect grrr in the output.

You aren't passing callback functions to `then` and `catch`. Your `console.log()` expressions will always execute — Phil, Sep 04 '19 at 00:07
I don't agree with the duplicate flag. My mistake was I gave an expression instead of a callback function. — rems14, Sep 04 '19 at 00:22
@rems14 - I'm sure there's an appropriate duplicate to your error - it's a very common mistake :p — Jaromanda X, Sep 04 '19 at 00:30

score 5 · Accepted Answer · answered Sep 04 '19 at 00:07

5

The then & catch should receive a callback function, you are calling console.log.

channel.send('heeeello')
.then(() => console.log('cool') )
.catch(() => console.log('grrr') );

answered Sep 04 '19 at 00:07

Tarek Essam

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21

That's true. It works now. Thank you! – rems14 Sep 04 '19 at 00:12

Why do both promise .then() and .catch() are called?

1 Answers1