discord-message-deleter.js

function createMessageDeleter({
                                  rateLimitMs,
                                  channel,
                                  authorization,
                                  xSuperProperties,
                                  authorId
                              }) {
    
    function deleteMessage(message) {
        if(message.author.id !== authorId) {
            return;
        }

        return fetch(`https://discordapp.com/api/v8/channels/${channel}/messages/${message.id}`, {
                credentials: "include",
                headers: {
                    "accept": "*/*",
                    "accept-language": "en-US",
                    "authorization": authorization,
                    "sec-fetch-mode": "cors",
                    "sec-fetch-site": "same-origin",
                    "x-super-properties": xSuperProperties
                },
                referrer: `https://discordapp.com/channels/@me/${channel}`,
                referrerPolicy: "no-referrer-when-downgrade",
                body: null,
                method: "DELETE",
                mode: "cors"
            }
        );
    }

    async function getMessagesBefore(message) {
        const response = await fetch(`https://discordapp.com/api/v8/channels/${channel}/messages?before=${message.id}&limit=50`, {
            credentials: "include",
            headers: {
                "accept": "*/*",
                "accept-language": "en-US",
                "authorization": authorization,
                "sec-fetch-mode": "cors",
                "sec-fetch-site": "same-origin"
            },
            referrer: `https://discordapp.com/channels/@me/${channel}`,
            referrerPolicy: "no-referrer-when-downgrade",
            body: null,
            method: "GET",
            mode: "cors"
        });
        return response.json();
    }

    async function recursiveDeleteAllMessages(messages) {
        if (messages.length > 0) {
            for (let index = 0; index < messages.length; index++) {
                await new Promise(r => setTimeout(r, rateLimitMs));
                await deleteMessage(messages[index]);
            }
            const lastMessage = messages[messages.length - 1];
            return recursiveDeleteAllMessages(await getMessagesBefore(lastMessage));
        }
        return true;
    }

    async function deleteAllMessages(startId) {
        const startMessages = await getMessagesBefore({id: startId});
        return recursiveDeleteAllMessages(startMessages);
    }

    return {
        deleteAllMessages
    }
}

const channelClient = createMessageDeleter({
    rateLimitMs: 600, //time between deletes
    channel: '', //get from developer console network request
    xSuperProperties: "", //get from developer console network request
    authorization: "", //get from developer console network request
    authorId: 0
})

//Pass the starting messageId
channelClient.deleteAllMessages(771015313470783529)
    .then((done) => console.log(done))
    .catch(error => console.log(error));