discord rest api get all messages from channel

api_discord_get_channel_messages.js

import fs from 'fs'
import fetch from 'cross-fetch';
import dotenv from 'dotenv';

dotenv.config();

const TOKEN = process.env.TOKEN || ''
const GUILD_URL = process.env.GUILD_URL || ''

class IGuild {
    id: string
    name: string
    constructor(guild: IGuild) {
        this.id = guild.id
        this.name = guild.name
    }
}

let guildChannels = await fetch(
    `${GUILD_URL}/channels`,
    {
        headers: {
            'authorization': TOKEN
        }
    })
    .then(res => res.json())
    .then((res: IGuild[]) => {
        return res.map(item => { return new IGuild(item) })
            .filter(res => !['Text Channels', 'Voice Channels', 'General'].includes(res.name))
    })

let channelsMessages = await Promise.all(guildChannels.map(async item => {
    const messageReq = await fetch(`https://discord.com/api/channels/${item.id}/messages`, {
        headers: {
            'authorization': TOKEN
        }
    }).then(res => res.json()).catch(err => console.log(JSON.stringify(err)))
    return messageReq
}
))

let mergeChannelsAndMessages = guildChannels.map((item, index) => {
    return {
        //@ts-ignore
        ...item, images: [...[].concat.apply([], channelsMessages[index].map(item => item.attachments)).map(item => item.url)]
    }
})

let finalObject = [...mergeChannelsAndMessages]

fs.writeFileSync('public/cache.json', JSON.stringify(finalObject), 'utf8')

I've seen "guilds" being thrown around here and there. To be able to read messages via API, MUST the server be a guild?
Don't normal text channels on normal friends-servers work?