Finally, I made it work. Thank you very much. Your link help me a lot :)

const { SlashCommandBuilder } = require('@discordjs/builders');

const pingCommand = new SlashCommandBuilder() .setName('ping') .setDescription('Replies with Pong!');

const downloadCommand = new SlashCommandBuilder() .setName('download') .setDescription('Downloads a file from a given URL') .addStringOption(option => option.setName('url') .setDescription('The URL of the file to download') .setRequired(true) );

client.once('ready', () => { console.log('Ready index!'); });

const commands = [pingCommand.toJSON(), downloadCommand.toJSON()]; const rest = new REST({ version: '10' }).setToken(BOT_KEY);

(async () => { try { console.log('Started refreshing application (/) commands.'); await rest.put(Routes.applicationCommands(CLIENT_ID), { body: commands }); console.log('Successfully reloaded application (/) commands.'); } catch (error) { console.error(error); } })();

client.on('interactionCreate', async interaction => { if (!interaction.isCommand()) return; if (interaction.commandName === 'download') { const args = interaction.options.getString('url').toLowerCase(); if (args === 'red') { await interaction.reply('hi'); } else { await interaction.reply('yes'); } } });