DiscordAPIError: Unknown application command - discord.js

Question

When I try to execute a slash command it crashes with an 404 error.
I already tried to delete all commands but it didn't work.
Here's the code I'm using
const commands = [
{
name: 'ping',
description: 'Replies with Pong!'
}];
const rest = new REST({ version: '9' }).setToken('token');
(async () => {
try {
console.log('Reloading slash commands');
await rest.put(
Routes.applicationGuildCommands("client_id", "server_id"),
{ body: commands },
);
console.log("Reloaded slash commands");
} catch (error) {
console.error(error);
}
})();
Here's the error
node_modules/discord.js/src/rest/RequestHandler.js:350
throw new DiscordAPIError(data, res.status, request);
^
DiscordAPIError: Unknown application command
at RequestHandler.execute (/home/container/node_modules/discord.js/src/rest/RequestHandler.js:350:13)
at processTicksAndRejections (node:internal/process/task_queues:96:5)
at async RequestHandler.push (/home/container/node_modules/discord.js/src/rest/RequestHandler.js:51:14)
at async GuildApplicationCommandManager.fetch (/home/container/node_modules/discord.js/src/managers/ApplicationCommandManager.js:93:23)
at async Client.<anonymous> (/home/container/index.js:101:17) {
method: 'get',
path: '/applications/client_id/guilds/guild_id/commands/command_id',
code: 10063,
httpStatus: 404,
requestData: { json: undefined, files: [] }
}

Answer 1

if you want to register your Slash Commands with the moderately recent Discord.js Rest library you have to use the builder library as well. You are also not passing JSON to the body you are passing an Array of Objects.
From Discord.js Guide on Making Slash Commands
const { SlashCommandBuilder } = require('#discordjs/builders');
const { REST } = require('#discordjs/rest');
const { Routes } = require('discord-api-types/v9');
const commands = [
new SlashCommandBuilder().setName('ping').setDescription('Replies with pong!'),
new SlashCommandBuilder().setName('server').setDescription('Replies with server info!'),
new SlashCommandBuilder().setName('user').setDescription('Replies with user info!'),
]
.map(command => command.toJSON());
const rest = new REST({ version: '9' }).setToken(token);
rest.put(Routes.applicationGuildCommands(clientId, guildId), { body: commands })
.then(() => console.log('Successfully registered application commands.'))
.catch(console.error);